Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/13/16
Area Forecast Discussion
National Weather Service Taunton MA
1016 PM EDT Wed Oct 12 2016
.SYNOPSIS...
As high pressure begins to shift east tonight, low clouds along
with patchy fog and drizzle will overspread the area. This will
be ahead of an approaching cold front, which will bring scattered
showers Thursday afternoon and evening. The front will push
offshore Thursday night into early Friday morning, followed by dry
and cool conditions. High pressure will keep dry and cool weather
into Saturday before temperatures moderate to near normal Sunday
followed by a warming trend for early to middle of next week.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
10 pm update...
Continued forecast challenges with low clouds, fog, and drizzle.
Let`s take a step back for a second and evaluate the environment.
0z soundings out of Upton NY and Chatham MA show a pronounced dry-
inversion ranging from 1-3 kft agl beneath which there is decent
low level moistening as within the last few hours dewpoints have
crept up into the 50s. Mostly clear conditions with light winds,
we`re tackling a few conditions centered around boundary-layer
cooling and moistening as radiational cooling proceeds ahead of
low clouds settling in. Also need to take into perspective that
during max heating of the day surface dewpoints ranged around the
mid to upper 40s, around if not higher than forecast overnight
lows around the low to mid 40s. All this as we begin to transition
into a period of height falls and cyclonic flow into morning ahead
of an approaching trough axis and accompanying cold front towards
afternoon and evening, in other words an increasing measure of lift
upon the low to mid level environment.
All this together combined with probabilistic guidance weighed in
from the HRRR Time Lagged Ensemble lends to confidence of low clouds
developing across much of S New England with patchy elements of
fog and drizzle. There appears to be a greater likelihood of fog
over N/W portions of the interior as clearing is forecast to be
more proficient and is already ongoing, while drizzle develops
more so to the E parent with the deeper moist onshore flow and low
clouds already developing over the lower CT River Valley.
Agree with the previous forecaster, sometimes the high-res guidance
can embellish on these situations with too much moisture, and us
as forecasters get blown out of the water with mud on our face. We
cry wolf and in the end it turns out dry with not much issue. But
given some of the signals and what is presently ongoing, have high
confidence with respect to low clouds with moderate confidence as
to specific fog and drizzle impacts. Will lean patchy rather than
widespread as the prior forecaster decided. Fog could be dense
with visibilities down to half a mile as we go into the morning
commute and have messaged that out accordingly to all partners.
Not enough confidence to go with a dense fog advisory but will be
monitoring closely.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
Thursday...
Should see the low clouds, patchy drizzle and fog end by around
mid morning. May even see a few breaks in the clouds inland. This
will occur as a cold front approaches from NY state. Pretty
vigorous H5 short wave associated with the surface feature, both
of which should approach eastern areas by evening.
Scattered showers will push into W MA/N Central CT by late
morning on Thursday, though timing is a bit in question, but
should steadily move across the region during the afternoon. Most
of the short wave energy will remain across northern New England,
and not a lot of QPF with it. Rainfall amounts will be light,
generally 0.1 inches or less, though may see a bit more across the
E slopes of the Berkshires.
Mild air works in across the region on the S-SW winds ahead of
the cold front, so temps will rise to the mid-upper 60s across
most areas.
Thursday night...
Cold front sweeps off the coast early Thu night. Winds shift to W
early, then NW by midday. Pretty tight pressure gradient as
another large high builds E out of the Great Lakes and Ohio
valley. Winds will be gusty, mainly along the coast around or
after midnight. Could see gusts up to 30-35 mph, highest across
the outer Cape and Nantucket.
Conditions improve around or after midnight as skies become
partly cloudy. Expect overnight lows in the 40s for the most part,
though could see a few upper 30s across the higher inland terrain,
and remaining in the lower 50s across Cape Cod and the islands.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
*/ Highlights...
* Dry and cool Friday and Saturday
* Temps moderate Sun and then possibly warmer than normal next week
* A few showers possible sometime Sun night thru Mon night
*/ Details...
Friday and Saturday...
Post frontal airmass overspreads the region with gusty north to
northwest winds late Thu night into Fri morning. Strongest winds up
to 30 mph will likely occur over Cape Cod and Islands where
relatively warm SSTs of low 60s near shore will promote a deeper
blyr for northerly winds to mix down. Winds diminish during the day
Friday as 1030 mb high builds into NY state Fri afternoon. Overall a
nice day by mid Oct standards with more sun than clouds (scattered
strato-cu) and highs climbing into the upper 50s and low
60s...coolest highest terrain. These values are just about normal
for mid Oct.
Chilly Fri night/Sat morning as 1030 mb crest over southern New
England. Clear skies...light winds and a dry airmass will allow
temps to plummet with sunset. Mins just before sunrise Sat should be
in the 30s throughout much of the region...with 40s along the coast
including Cape Cod...islands and the cities of Boston and
Providence. Outside of this region expect widespread frost with a
freeze possible in the CT river valley of western MA.
A chilly start Saturday as 1030 mb high remains overhead and limits
blyr mixing. This subsidence inversion will limit highs to the mid
to upper 50s...which is cooler than normal. However these cool temps
will be offset by abundant sunshine and light winds.
Sunday...
Surface ridge begins to move offshore and weaken with pressure down
to 1022 mb or so. This will promote surface winds to shift to the
SSW with weak low level waa occurring along with slightly deeper
blyr mixing. So despite another chilly start to the day Sunday
afternoon temps will rebound a bit more than Sat with highs 60-65
by late Sunday...along with partly to mostly sunny conditions.
Monday thru Wednesday...
Mixed signals within the model data. 12z GEFS and 00z EPS both have
a warm signal for much of next week as subtropical ridge builds
northward into the mid atlc region...leaving southern New England on
the northern periphery of the ridge. This is somewhat of a tricky
forecast as northern stream short wave energy riding the northern
periphery of the ridge could easily suppress warmth from surging
northward into southern New England Mon and Tue. This jet energy may
bring the risk for a few showers to the area Sun ngt thru Mon night.
The issue appears to be how models handle jet energy associated with
extratropical remnants of Songda...which comes onshore into
Washington state this weekend. This will impact the amplitude of
northern stream energy moving across the Northeast around Monday.
Nevertheless expecting at least one or two mild to warm days next
week with highs possibly 70+ degs as GEFS advects +14c airmass at
925 mb into the region. 00z EPS has warm signal as well with 50%
probs for 70+ and even low probs of 80+ Tue and Wed.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
Forecaster Confidence Levels.
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Short Term /through Thursday Night/...
2z update...
Through 00Z...High Confidence. VFR. Light S winds.
Tonight...Moderate Confidence.
VFR early. Lowering MVFR to LIFR towards midnight. Leaning low
cigs over much of the terminals with VSBY impacts across the N/W
(CT River Valley) with DZ more S/E. Light S winds.
Thursday...Moderate Confidence.
Low end MVFR-LIFR conditions early, then improving to low end VFR
by mid to late morning. Line of SCT SHRA during the afternoon into
evening hours sweeping terminals W to E with accompanying brief MVFR
cigs, possibly VSBY issues. Breezy S winds around 10 to 15 kts with
possible gusts up to 20 kts.
Thursday night...Moderate Confidence.
Conditions improving to VFR. Any leftover SHRA end by 04Z. Winds
shift to NW gusting to 20-25 kt along the coast mainly after midnight,
but may approach 30 kt toward daybreak across outer Cape Cod and
Nantucket.
KBOS TAF...VFR to start, then MVFR-IFR CIGS moving in around 06Z
or so. Lean more patchy DZ with VSBY restrictions down to MVFR
through mid morning Thursday. Low CIGS continue through midday
Thursday, then should improve to low-end VFR before SCT SHRA move
in late afternoon into evening. Moderate confidence mainly for
exact timing.
KBDL TAF...Low-end VFR to MVFR mix lowering towards IFR beginning
midnight. Perhaps some patchy DZ but greater confidence of dense
fog with IFR-LIFR VSBYs towards the morning push. Improving into
the mid-morning hours to low-end VFR prior to a line of SCT SHRA
sweeping the terminal during the afternoon.
Outlook /Friday through Monday/...
Updated 4 pm...
Friday...High confidence.
Mainly VFR conditions. However, some ocean effect MVFR clouds
possible across the Cape/Islands with cool northerly flow.
Northerly wind gusts of 20 to 30 knots with the strongest winds
across Cape/Nantucket.
Saturday and Sunday...
High confidence in VFR conditions into Sunday
Sunday night and Monday...
MVFR conditions in scattered showers possible but low confidence.
&&
.MARINE...
Forecaster Confidence Levels.
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Updated 5 pm...
Short Term /through Thursday Night/...
Through Thursday...High confidence.
Winds and seas are below small craft criteria through Thursday.
Visibility restrictions with drizzle overnight tonight into
Thursday morning, then scattered showers move across Thursday
afternoon/evening with a passing cold front. S winds ahead of the
front with gusts up to 20 kts, shifting W/SW with passage
continued breezy.
Thursday night...Moderate confidence.
Winds continue to shift to W-NW and increase, gusting to 25-30 kt
mainly after midnight. S-SE swells also begin to move into the
outer waters ahead of Hurricane Nicole, passing well SE of the
waters.
Outlook /Friday through Monday/...
Friday...High confidence.
NNW winds 20-30 kt thu night into Fri morning...strongest winds
eastern MA waters. Seas could be extra choppy across the eastern
MA waters as gusty northerly winds oppose SE swells from distant
hurricane Nicole. Winds slacken Fri afternoon. Good vsby and dry
weather too.
Saturday and Sunday...High confidence.
Tranquil boating weather with high pressure overhead yielding
light winds becoming SSW Sunday. Dry weather and good vsby. Only
wrinkle will be building east swells across the eastern MA ocean
waters from distant Hurricane Nicole.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from 1 AM to 6 AM EDT Friday for
ANZ231>234-251.
Small Craft Advisory from 11 PM Thursday to 6 AM EDT Friday
for ANZ235-237-250.
Small Craft Advisory from 6 PM Thursday to 6 AM EDT Friday for
ANZ254>256.
&&
$$
SYNOPSIS...Nocera/EVT
NEAR TERM...Nocera/Sipprell/EVT
SHORT TERM...EVT
LONG TERM...Nocera
AVIATION...Nocera/Sipprell/EVT
MARINE...Nocera/EVT
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1158 PM EDT WED OCT 12 2016
.AVIATION...
Extensive stratus filling in behind a cold front will hold firm
through the morning period. Ceiling heights will largely remain at
lower MVFR restrictions, although a brief dip into IFR will remain
possible early this morning. Gusty post-frontal northwest wind will
ease with time through the morning period. Clearing likely a slow
process Thursday, given a high degree of lingering low level
moisture tucked beneath the inversion.
For DTW...Gusty northwest flow early this morning will ease toward
sunrise. Northwest winds hold through the day. High confidence in
ceiling below 5000 ft this morning. Lower confidence in timing of
clearing Thursday afternoon/evening.
//DTW Threshold Probabilities...
* High for ceiling below 5000 ft through Thursday morning...then
medium Thursday afternoon.
&&
.PREV DISCUSSION...
Issued at 409 PM EDT Wed OCT 12 2016
DISCUSSION...
As of 19Z, the primary synoptic scale cold front is in place over
sections of far southeastern Wisconsin and northern Illinois. The
main theta e corridor is east of the cold front with the low level
moisture max over western lower michigan. The lead edge of the theta
e corridor just now pushing into southeastern Michigan, with a low
to midlevel cyclonic circulation attached to this boundary over far
northern Illinois. Model data ejects the cyclonic circulation
northeastward while shearing out, pushing near the Saginaw Valley
and Saginaw Bay around 00Z this evening. The added warm advection
provided by this cyclonic circulation will provide the push to begin
precipitation for this event. Model data has been a little noisy the
past 24 hours both with regards to both the start times for
categorical rain chances and the end time of the event.
Latest hi res explicit convection allowing solutions have slowed the
onset, to as late as 23-00Z. Current trends of convection
initiating over western Lower Michigan casts doubt on that slow of
timing, but the categorical rains should fall between 23-05Z. Main
item to monitor is the potential for thunderstorm activity during
the next 3 to 6 hours. Latest observational analysis including the
RAP based mesoanalysis supports SBCAPE of between 500-1000 J/KG with
ML CAPE of around 500 J/KG. Evolution of forecast CAPE is bearish
with the integrity of the surface based instability ribbon as it
arrives locally. As a result, not overly excited about strong wind
potential with the convection but there has been enough surface
observational evidence to support that gusty winds will be possible
with this convection. An isolated wind gust to 40 mph will be
possible this evening.
Data has really abandoned the solution that supported a secondary,
separate fgen response later tonight. The overwhelming trend has
been to consolidate both the fgen response with the main warm air
advection support and right entrance region dynamics. Thus, expect
the bulk of the rain to push out of the area already by 06z. There
may be some lingering drizzle for a time as low level cold air
advection ramps up, but the model signal is not overly strong there.
A big change to the forecast was to increase clouds substantially
for Thursday in the wake of the cold front. Satellite and surface
observations have shown stout stratus in place over the Eastern
Dakotas today directly within the eastern hemisphere of the surface
high pressure. A very good structure to the low or midlevel
subsidence inversion supports keeping cloud, moisture, saturation
locked in. Did go aggressive with clearing trend in the late
afternoon. Did lower the offered guidance by a degree or two, but
still could be too warm. Current surface temperatures this
afternoon over portions of Wisconsin remain in the middle 40s.
Sprawling surface high pressure will be in place for Thursday night.
Numbers come in a little cooler with these successive runs. At this
time, looks like a good bet on frost advisories for just about
everyone, and may need to even look at possible Freeze Warnings
especially across the northern CWA.
High pressure centered over the Northeastern US and low pressure
centered over Manitoba/Ontario allow southerly winds to bring in
warm air, pushing temperatures into the the mid to upper 60s for a
daytime high, with a shot at 70 closer to the MI/OH border on
Saturday. As low pressure moves further east into Ontario, it will
drag along with it a cold front through Michigan, which is expected
to bring scattered showers with a rumble of thunder possible into
the region. Next week looks to be a fairly active one as a series of
low pressure systems from the Central Plains pushes northeast into
Michigan. As the lows move over us, the chance for additional rain
showers will exist. Otherwise, the early part of next week looks to
remain mild as 12-15C 850 mb temps sits over the region.
MARINE...
The strongest wind event of the young autumn season is getting
underway as gusty fresh southerly flow continues to develop in
advance of an approaching cold front. Passage of the front will
bring a sharp shift in winds to northwesterly with near-gales likely
across the open waters of Lake Huron and possibly the exposed
nearshore waters of the Thumb. Brief or isolated gale-force wind
gusts will be possible but are forecast to be short-lived. The
highest liklihood of gale-force wind gusts will be along the front
itself. Significant wave heights will approach 10 feet over the open
waters of central Lake Huron. Small craft advisories remain in
effect for nearshore zones.
HYDROLOGY...
Abundant moisture streaming north in advance of a strong cold front
will bring widespread showers tonight. Showers are forecast to reach
the Saginaw Valley area around 6 PM local time eventually reaching
the Detroit Metro area between 8 PM and 9 PM. Widespread rainfall
amounts approaching one half inch are expected with the heaviest
rain falling prior to 11 PM at all locations.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...Gale Warning until 4 AM EDT Thursday FOR LHZ362.
Small Craft Advisory until 5 AM EDT Thursday FOR LHZ422.
Small Craft Advisory until 10 AM EDT Thursday FOR LHZ421-441-442.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&
$$
AVIATION.....MR
DISCUSSION...CB/AM
MARINE.......JVC
HYDROLOGY....JVC
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Grand Forks ND
922 PM CDT Wed Oct 12 2016
.UPDATE...
Issued at 922 PM CDT Wed Oct 12 2016
Made some adjustments to the cloud forecast, as the clearing line
has finally moved into the Red River Valley. It could take until
midnight or a little later for this clearing line to reach the
Baudette to Bemidji corridor.
&&
.SHORT TERM...(This evening through Thursday)
Issued at 212 PM CDT Wed Oct 12 2016
The forecast challenge for tonight will be sky trends and impacts
on overnight lows. Current vis imagery showing stratocu across
majority of area with a hole over the Grafton area. Back edge of
cloud cover vcnty of Missouri river basin should arrive in
western zones around 23Z to 00Z per HRRR low layer RH field.
CONSSHORT is slightly slower clearing out southeast ND and do
prefer the slower solution, however with cellular nature of clouds
do expect some gradual dissipation along with clearing line
advecting east. Less confidence across the north where HRRR keeps
mostly cloudy skies across portions of northwest MN through the
overnight period. However, given trends to the west along intl
border, does appear modeled low level RH and sky cover may be
overdone. Winds will become lightest in the mid evening hours as
sfc ridge shifts east of the CWA and westerly winds subside before
turning southwesterly for remainder of night.
Overnight lows will fall into the mid-20s by morning if
widespread clearing does occur...bringing the coldest night and
hardest freeze...of this fall. Issued a special weather statement
declaring an end of the growing season with no further frost or
freeze products planned for 2016.
Full solar but weak flow will allow daytime highs to rebound into
the mid 40s to upper 50s, from north to south, across the region
on Thursday. Any stronger than expected mixing across the south
could bump temperatures above the 60 mark, but the warmest
temperatures will arrive in the early part of the long term
period.
.LONG TERM...(Thursday night through Wednesday)
Issued at 212 PM CDT Wed Oct 12 2016
Models begin the long term period Thursday night in good agreement
with 500mb zonal flow aloft. 850mb WAA and strong LLJ, increasing to
30 to 40kts, persisting through the day Friday into Friday night
will allow max temps to rise into the 60s to end the week with
strong south winds turning to the west for Saturday. SFC trough will
push through on Friday night or early Saturday morning with limited
moisture. Will keep a slight rain mention confined to the northern
areas late Friday into Saturday.
By Sunday afternoon the next shortwave in the SW flow aloft begins
to influence the region. Increasing chances for showers and possibly
an isolated thunderstorm into the evening hours with showalters
around zero and a strong LLJ nosing into the southern valley. Models
begin to diverge with their solns by Monday with the energetic 500mb
flow. The GFS continues to wind up a storm system in the central
plains whereas the ECMWF maintains a more progressive soln.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 620 PM CDT Wed Oct 12 2016
Should seeing clearing entering the KDVL area around 00Z and at
KGFK/KFAR about an hour or so later. This clearing will probably
not get to KTVF and KBJI until mid to late evening. Otherwise
winds will stay light throughout.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...Godon
SHORT TERM...Speicher
LONG TERM...JK
AVIATION...Godon
Area Forecast Discussion
National Weather Service Wilmington OH
1035 PM EDT Wed Oct 12 2016
.SYNOPSIS...
A cold front will move through overnight into early Thursday,
bringing showers and cooler weather to the region. High pressure
will build in providing dry weather and cooler temperatures. A
weak upper level disturbance will offer the next chance for rain
late Friday night.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Prefrontal shower activity still ongoing across our north and
east, but rainfall amounts have been rather unimpressive given
limited moisture in place. The cold front itself currently
stretches from northwest Ohio down through southwest Indiana with
largely unorganized shower activity along it. Last couple runs of
the HRRR and RAP now develop a cluster of showers over southwest
Indiana (where low level convergence will be stronger) and carry
this activity northeast along the front across ILN`s south after
06Z. This activity will be enhanced by some weak mid level energy,
but deeper shortwave trough will remain over northern Ohio. Have
bumped up PoPs a bit more across our southwest to account for
this. Moderate CAA will kick in behind the front, but given the
late arrival of the front in our southeast, have nudged min temps
up by a few degrees there.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
Progressive shortwave to push east through the eastern Great Lakes
early Thursday. Associated surface front to push east through se
Ohio early Thursday. A few lingering showers will come to an end
early. In westerly flow pattern, surface high pressure to build
into the region, becoming centered over Ohio by Thursday evening.
Temperatures will be around 5 degrees below normal with highs
ranging from the upper 50s nw to the middle 60s se.
Surface high pressure to build east across the region Thursday
night. Good radiational cooling setup with lows by Friday morning
from the mid 30s ne to the lower 40s sw. Will continue to mention
patchy frost ne.
Upper level ridge to build across the region Friday. Expect mostly
sunny skies early with an increase in mainly high level clouds
during the day. Highs Friday to range from the lower 60s north
to the mid 60s south.
Weak shortwave to track from the plains into the Ohio valley
Friday night/Saturday. Will limit pops to chance category across
the far south late.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Period starts with a broad low amplitude upper ridge across the
eastern CONUS, with extensive surface high pressure centered along
the Atlantic Coast. Models show a couple of weak disturbances aloft
which may trigger a few showers over southern locations on Saturday.
For Sunday, a frontal boundary sagging south into the Great Lakes is
forecast to provide focus for showers, especially in northern
locations. Latest ECMWF indicates a vigorous wave of low pressure
developing along the boundary on Monday, causing the front to lift
farther north and bringing and end to shower chances. Low chances
for showers will linger Tuesday and Wednesday with the boundary
remaining in the vicinity of northern Ohio.
Above normal geopotential heights and a southerly low level flow
signal warmer than normal temperatures. Highs through the period
will range from the lower 70s to lower 80s, compared to normal highs
in the lower to middle 60s.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
Scattered showers out ahead of an approaching cold front will move
through the area this evening. Visibilities and ceilings should
generally remain VFR with these. The front has made it through NW
Indiana and will sweep through the terminals early Thursday
morning. Not a lot of moisture associated with this front, and
latest HRRR/RAP runs have been trending towards less shower
activity with it as it moves into Ohio. Have therefore only gone
with VCSH for early Thursday. Main aviation impact during this
forecast period will be MVFR to IFR ceilings that move in with the
front after 06Z Thursday. Drier air will begin to filter in after
daybreak, which will lead to a gradual improvement to these low
ceilings by afternoon, when skies will become mostly clear. SSW
winds this evening will veer to the NW with the frontal passage
early Thursday, then to the N for the remainder of the TAF period.
Some gusts to around 15 knots may accompany the frontal passage.
OUTLOOK...MVFR ceilings and visibilities possible Saturday and
Sunday.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...AR
NEAR TERM...Kurz
SHORT TERM...AR
LONG TERM...Coniglio
AVIATION...Kurz
Area Forecast Discussion
National Weather Service Nashville TN
900 PM CDT Wed Oct 12 2016
.DISCUSSION...
Latest radar imagery shows a few showers have developed near
Clarksville, with a more extensive area of light to moderate rain
approaching our northwest zones from the west. HRRR model brings
this activity into the CWA overnight but diminishes it quickly as
it encounters the much drier airmass in place over Middle
Tennessee, as shown by the PWAT of only 1.12 inches on the 00Z OHX
sounding. Thus will keep ongoing slight to chance pops in place
from Nashville northwestward, but did nudge them up a tad over the
northwest counties. Rest of forecast appears to be on track and
just made updates based on latest obs.
&&
.AVIATION...
00Z TAF DISCUSSION.
VFR with periods of MVFR possible at KCKV and KBNA. Chances for
showers will move in with a cold front from the northwest during
the TAF period, and mainly impact KCKV. Some showers may make it
to KBNA tomorrow morning, but confidence is slightly higher for
KCKV. Models are also showing MVFR cigs for KCKV and even KBNA
tomorrow morning and possibly even into the afternoon. Have
mention of MVFR cigs at those terminals with a longer duration at
KCKV. Conditions should return to VFR for KBNA and KCKV by the
later afternoon hours on Thursday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 58 72 53 73 60 / 20 20 10 40 40
Clarksville 55 68 49 70 57 / 50 20 10 40 40
Crossville 52 72 50 72 54 / 10 10 10 20 40
Columbia 55 75 54 74 58 / 10 10 10 40 40
Lawrenceburg 54 77 54 75 59 / 10 10 10 30 40
Waverly 57 68 52 70 58 / 30 10 10 40 40
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION......Shamburger
AVIATION........Barnwell
Area Forecast Discussion...UPDATED
National Weather Service Norman OK
840 PM CDT WED OCT 12 2016
.UPDATE...
Increased overnight lows and cloud cover in most locations
tonight.
&&
.DISCUSSION...
Cooler conditions will occur tonight with surface winds slowly
decreasing. Think any rainfall will hold off until after 6 am
Thursday.
Latest satellite imagery as of 815 pm depicted abundant low level
cloud cover (generally 1500-6000 ft AGL) roughly 60 miles north
and south of an Altus to Oklahoma City to Chandler line. The
surface cold front had pushed south of Durant Oklahoma as of 815
pm.
Based on the satellite imagery and HRRR guidance, think cloud
cover will continue to increase across the area. The low cloud
shield should expand north and especially south. High level cloud
cover will increase from the west as well.
As a result of more clouds, do not think low temperatures will
fall significantly where the low cloud cover currently exists.
Thus, increased lows a few degrees. The coldest lows are still
expected in northwestern Oklahoma around 40 degrees. Think
abundant high level cloud cover will limit radiational cooling in
far northwestern Oklahoma and prevent lows from falling in the
mid 30s as well as any potential for patchy frost.
The low level moisture may be just deep enough for some patchy
drizzle to form after midnight near the line mentioned above.
Chances of occurrence appear to be too low to mention at this
time. Showers and a few weak thunderstorms should begin to form
over west Texas around 4 am tonight then expand east and
northeast during the morning hours on Thursday.
Products will be updated shortly.
MBS
&&
.PREV DISCUSSION... /issued 652 PM CDT WED OCT 12 2016/
DISCUSSION...
00Z TAFS.
AVIATION...
Cold front has moved through all of the TAF sites. Post-frontal
stratus with MVFR ceilings will persist, and likely even expand
in coverage tonight. Gusty north winds will diminish early this
evening, and should start to come around at the western sites
Thursday afternoon. Precipitation chances will expand from west to
east across Oklahoma and north Texas on Thursday.
PREV DISCUSSION... /issued 330 PM CDT WED OCT 12 2016/
DISCUSSION...
Strong cold front will continue to push south this evening with
a cooler night on tap with diminishing winds. A much cooler
day expected on Thursday with much of the area only warming into
the 60s, with some places not climbing out of the 50s.
In addition to the cooler temperatures, a disturbance will move
out of the southern Rockies into the Southern Plains. This will
bring a good chance of rain along with a few thunderstorms,
especially Thursday afternoon and night. No severe weather is
anticipated as instability will be rather limited. A few
locations across southern Oklahoma near the Red River could pick
up in excess of an inch of rain before all is said and done,
which should be Friday late morning.
In the wake of this system, a quick warm-up is expected into
the weekend with gusty south winds. Much of the area could see
daytime highs in the 90s Saturday through Monday. Another front
will bring some cooler air back into the area by Tuesday, but
this front looks to come through dry.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 53 61 54 76 / 10 50 60 20
Hobart OK 54 59 53 77 / 10 60 50 10
Wichita Falls TX 51 65 56 80 / 10 50 60 40
Gage OK 42 60 48 80 / 10 50 20 0
Ponca City OK 49 61 51 75 / 0 30 50 10
Durant OK 54 69 59 79 / 10 40 70 50
&&
.OUN Watches/Warnings/Advisories...
OK...None.
TX...None.
&&
$$
17/26
Area Forecast Discussion
National Weather Service Denver/Boulder CO
333 AM MDT Thu Oct 13 2016
.SHORT TERM...(Today and tonight)
Issued at 310 AM MDT Thu Oct 13 2016
Dry westerly flow aloft continues over Colorado through Thursday
night with no precipitation expected area-wide and much warmer
temperatures across the Plains. The low clouds from Wednesday have
dissipated overnight. There is also a weak short wave trough
currently moving east out of Utah and into Colorado which is
generating a mid-level cloud deck. The low-level moisture is
hanging around this morning and so fog is a concern. Fog has
already developed across Weld County with Greeley reporting 1/4M
Visibility. However, surface and satellite obs combined with HRRR
and RAP model output have consistently kept the fog north of the
C-470 beltway and Denver International airport. Weld and Morgan
counties primarily will see some fog between now and a few hours
after sunrise but the fog could sneak into the northwest side of
the Denver metro area. Will continue to monitor observations for
fog advection into the metro area this morning.
During the day today temperatures rebound in a big way as the
low-level moisture is scoured out with low-level southwest flow,
and strong subsidence is parked over the state. Temperatures
across eastern Colorado should reach the mid 70s under partly
cloud skies, a 20-25 deg improvement over Wednesday. The mountains
should see similar temps compared to Wednesday with 50s and lower
60s. With much warmer 700 mb temps and continued subsidence, low
temperatures Thursday night into Friday morning will also be 10
degrees warmer across the Plains and should not see a repeat of
fog/stratus.
.LONG TERM...(Friday through Wednesday)
Issued at 310 AM MDT Thu Oct 13 2016
Height rises on Friday perpetuated by the passage of a flat
shortwave upper ridge will result in unseasonably warm
temperatures across the CWA. The presence of a low amplitude mtn
wave will further enhance warming along the Front Range with
downslope flow gradient in place. However wind speeds should not
be all that strong due to a flat pres gradient across the area.
Although the high country could see gusty west-southwest winds
developing by afternoon esply over the high ridges and peaks as a
50-70 kt mid-level speed maxima passes over Wyoming. Could see
gusts in the 30-45 mph range in the higher exposed areas. Highs
on Friday are expected to range from the low/mid 80s on the plains
to 60s and lower 70s in the mtns and high valleys. These readings
are some 12-16 deg f above average for the date. If it were not
for the light winds...the high temps...low RH and unstable bndry
layer...I would need to consider hoisting a fire weather watch
for the plains...as well as for Middle and South Parks as dry
grasses remain abundant even after chilly drippy weather
yesterday.
Saturday and Sunday...look nearly as warm and dry with the upper
ridge slowly slipping east of the area. Winds remain relatively
light except on the higher mtn ridges and peaks which protrude up
into the relatively strong zonal flow aloft. Will continue to
nudge red flag conditions at a few spots on the plains and high
valleys with low RH and warm temps...but wind speeds thankfully
will still be too weak for that.
Early part of next week...models show a buckle in the zonal flow
and a shortwave trough carving out over the northern Great Basin.
Flow aloft turns southwesterly over Colorado and temps aloft begin
to cool. Models also show moistening across the nwrn corner of
the state on Monday...with further moistening and cooling over
the northwest corner of the CWA by Monday night and Tuesday. Low
pops seem in order across this part of the CWA with precip
starting out as rain. As temps cool should see the snow level
leveling to around 9500 ft in the nrn mtns late Monday night and
Tuesday morning. But any snow accumulation should be spotty and
minuscule. While areas east of the mtns should remain dry...although
some of the models notably the ECMWF indicate spotty light QPF
over northern portions of the plains Tuesday aftn and overnight.
The GFS and DGEX indicate nothing. By Wednesday all models show
amplification of the upper trough now just east of Colorado which
places the CWA under a cooler and stronger northwest flow regime.
It`s a bit too early to know if we`ll see measurable precip with
the upslope flow models suggest on Wednesday. Will hold off
mentioning any east of the mtns for now. But it should turn
cooler Wednesday and Thursday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 310 AM MDT Thu Oct 13 2016
Winds are currently SSW at KDEN and are expected to remain
generally that direction until mid- day. An area of fog has
developed across Weld County but with the SSW low- level flow
across KAPA and KDEN we do not expect the fog to impact either
terminal but it will get close. HRRR and the Experimental HRRR
have consistently kept the fog away from the terminals, but given
how close it comes if there is any deviation in low-level flow
towards the NNW the fog could be advected to KDEN. Will be
closely monitoring those trends to provide as much heads up as
possible if conditions change for KDEN. KBJC has a better chance
of fog between 10-14UTC and covered that with a tempo group for
now. Expect very little impacts to terminals during the day and
through Thursday night with VFR conditions and generally light
winds.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...Schlatter
LONG TERM...Baker
AVIATION...Schlatter
Area Forecast Discussion
National Weather Service State College PA
604 AM EDT Thu Oct 13 2016
.SYNOPSIS...
A cold front will pass through the commonwealth during
the morning and midday hours. High pressure will move back in for
Friday and Saturday with fair weather and cool nights, but
daytime temperatures returning to above normal.
&&
.NEAR TERM /THROUGH TONIGHT/...
Forecast remain consistent in most respects. Very light shower
sliding across Warren Co at 07Z with additional rain showers
speckled about wrn PA, and a larger area of showers more along the
front which runs from KCLE to KDAY. Wind shift is obvious. The
main change with this package was to allow for a tiny bit faster
onset and ending - basically tightening up the waggle room we felt
was necessary during the mid-day and aftn. But, most/all guidance
ends precip for central PA by 18Z - both pushing it east of the
area and drying it up. Will continue with high POPs for the NW
half - but many locations SE of KAOO- KUNV- KIPT may only get a
few sprinkles this morning. Dry fronts are usually windy fronts
and have therefore tried to paint slightly higher than guidance
winds/gusts for the late morning and all afternoon.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
Cross-lake flow will make a few lake effect clouds in the evening,
but it should clear out completely early tonight. A light
gradient wind will be left for at least the first half if not all
of the night in the southeast where the growing season is on-
going. The wind will be just about the only factor preventing a
frost in those locations. The clear skies will help temps drop
into the m30s-l40s there. Northern and western locations will drop
below freezing tonight, but we probably do not need to mention
frost since the growing season is over there. Will just mention to
next shift for possible mentions/advy if it looks like it will be
more- calm than it looks at this point.
High pressure moving in will ensure that Friday will feature
abundant sunshine and a light N/NE wind. Maxes will be a few
degrees below normals, but the sun should make it feel milder.
Friday night/Sat AM is the most interesting period in the short
term as the high should be overhead. Temps will likely get cold
enough and wind will be light enough to allow a widespread frost
in the SErn half where the growing season continues. Have
continued the mention of frost for Sat AM in the HWO, but it is
far too early for an advy - esp if we need to consider one for
tonight. Would not be surprised to see THV and SEG get down to
freezing. But these outliers will not be enough to make me think
a freeze watch is necessary.
Saturday will be another sunny and mild day. Temps will get 3-5F
warmer than Friday over most of the area - with the NW as much as
10F warmer.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
A frontal system accompanied by a band of showers will reach the
area late Sunday into Sunday night, with enough agreement and
ensemble support likely POPs over the northwest half of the CWA.
Rainfall amounts should be <0.50 inch.
The pattern looks somewhat unsettled heading into next week as
the area remains within fast quasi-zonal flow downstream of mean
western trough and north of upper ridge over the northern GOMEX.
Any shower activity would likely be periodic on the light side.
There is better than average confidence with respect to temps
which should trend milder and average above climatological normals
into the second half of the month.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
Main aviation concern early this morning is the fog/low cigs,
which have formed over Southeast Pa. Both KMDT and KLNS reporting
LIFR conditions as of 10Z. A cold front approaching from the west
has spread showers and lowering cigs across the western half of
the state early this morning, with MVFR cigs noted at KBFD at 10Z.
The cold front is progged by all models to track from KBFD around
13Z to KLNS around 18Z. A period of moist upslope flow accompanying
the front is likely to produce a brief period of IFR cigs at KBFD
between 12Z-15Z. At KJST, a similar period of moist upslope flow
immediately following the fropa is likely to produce a period of
IFR cigs between 14Z-16Z. Further east, an increasing southwest
breeze ahead of approaching cold front should help to disperse fog
across Southeast Pa by around 14Z based on latest HRRR guidance.
Otherwise, VFR to high MVFR cigs expected to accompany the frontal
passage during the late morning and early afternoon. The arrival
of drier air is likely to result in a return to widespread VFR
conditions beginning late this afternoon.
Outlook...
Fri...AM fog possible, esp KBFD.
Sat...No sig wx expected.
Sun...PM showers cig reductions possible north.
Mon...Showers cig reductions possible, mainly north.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Dangelo
NEAR TERM...Dangelo
SHORT TERM...Dangelo
LONG TERM...Steinbugl
AVIATION...Fitzgerald
Area Forecast Discussion
National Weather Service Louisville KY
401 AM EDT Thu Oct 13 2016
...Forecast Update...
Issued at 400 AM EDT Thu Oct 13 2016
We are reminded that weather is a very humbling field... as we`ve
been watching the puny precipitation pattern all night long, waining
through 320 AM. In the last 30 minutes or so, the LLJ and some warm
advection has increased the activity across the southern tier. All
night long, the models had been trying to paint a picture of
increasing POPs and the HRRR had been advertising it since 4Z, and
alas, by 730Z it`s coming to fruition across the southern areas.
We just updated the POP and WX grids to account for 40% POPs for
showers from Ohio County through Barren and over to the southern
Bluegrass counties between 9-13Z. Update will be coming soon.
.SHORT TERM (Now through Friday)...
Issued at 253 AM EDT Thu Oct 13 2016
Today and Tonight...
Early this morning, a cold front extends from TOL to IND to near
PAH. Scattered showers out ahead of this have fizzled out as they
approach Kentucky, but a stray shower is not out of the question
especially across central and southern parts of the CWA. Cloud cover
and much cooler temperatures will be the main event across the
region today as overcast to mostly cloudy conditions will prevail
into the mid afternoon. The back edge of the cloud cover is
currently situated near DBQ to UIN and will be slow to reach our
area due to ample moisture before drier air moves in late in the day
and into Friday.
Temperatures today will remain in the mid 60s for much of the area,
with slightly warmer readings south, but breaking into the 70s will
be a struggle thanks to the cloud cover. In fact, it is very likely
that we have already seen our 24 hour high for today. The 1000-850mb
thickness values drop significantly behind the front with decent
cold advection. Skies will begin clearing from northwest to
southeast around 19-21Z as cool Canadian high pressure moves in.
This will allow temperatures overnight to fall into the upper 40s in
the Bluegrass and low to mid 50s for points south. A few readings
closer to 40 are possible north of I 64, such as FFT, Lexington
IN, and Cynthiana.
Friday...
The main story for Friday is the cloud cover moving ahead of the srn
stream system moving out of TX into the Ozarks. The timing of the
cloud cover will have a profound affect on high temps. If the mid
and high clouds move in quicker temps may not get out of the 60s.
For now, made a minor downward tweak in max temps.
.LONG TERM (Friday Night through Wednesday)...
Issued at 245 AM EDT Thu Oct 13 2016
...Couple of weak systems Fri Ngt and Sunday...
...Major warm up next week...
1st System...
Well...the pattern starts off zonal with a weak system pushing out
of the Land of Enchantment and the Lone Star State towards the CWA.
The models moisture availability lift are marginal and will keep the
theme of chc pops, with not enough instability to warrant TSRA and
keep the most prominent pops south of I 64, and highest S of BG
Parkways for Friday night into mid morning Sat. Cloud cover will
take its time to depart Saturday, especially over the Bluegrass.
Could be a 5-10 degree temperature spread from Richmond/LEX/
Winchester in the cloud cover Saturday to Rough River/Beaver Dam/BWG
where the sunshine will be.
2nd System...
The next feature is a cold front from the northwest which will be
juxtapositioned from Hudson Bay to ORD to STL Sunday sunrise. This
is slated to drop into Indiana Sunday afternoon through Monday and
have difficulties pushing very far south. As the front approaches,
it becomes orientated west-east and stall out north of the Ohio
River. This is where the highest chances of showers will be found.
There is some limited instability with this and will keep the slgt
chance TSRA. The POP gradient will be stout, with the emphasis N of
I 64.
The major story of the entire forecast is the herculean ridge
developing over TX and moving into the heart of Dixie. The 592 m
high will bring very warm temps to the Mid and Deep South Mon-Wed.
H9 and H8 temps are 1-2 standard deviations above normal and will
bring temps into at least mid 80s and with the very dry vegetation,
upper 80s are plausible.
Beyond that, model guidance suggests another cold front will be
moving into the Ohio Valley in the Wed-Thu timeframe, but timing and
strength differences between the various deterministic and ensemble
guidance lowers confidence. A model consensus approach puts slight
chances across most of the area.
&&
.AVIATION (06Z TAF Update)...
Issued at 100 AM EDT Thu Oct 13 2016
Cold front dropping SE through southern Indiana, but the light
precip shield along and ahead of it continues to erode. Confidence
in the precip aspect of these TAFs is fairly low, but the more
important question is the impact of the post-frontal stratus shield.
Whether we carry VCSH or prevailing SHRA will be a last-minute
decision to hopefully incorporate latest radar trends and as much
short-term guidance as possible. If we can go VCSH, could free up a
line to better handle the cloud trends.
Best precip chances 08-12Z, give or take an hour, but during that
time frame ceilings will drop into fuel-alternate as the boundary
layer saturates. BWG and LEX could even dip into IFR, especially
after a daybreak fropa brings winds around to the north.
Expect ceilings to lift later in the day, getting above the fuel-
alternate threshold early/mid afternoon but not scattering out until
early evening.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........JDG/MED
Short Term.....JDG/MED
Long Term......JDG/MED
Aviation.......RAS
Area Forecast Discussion
National Weather Service Saint Louis MO
355 AM CDT THU OCT 13 2016
.SHORT TERM... (Through Late Tonight)
Issued at 343 AM CDT Thu Oct 13 2016
A seasonably cool day is expected as expansive surface high pressure
dominates the area. The high pressure center will shift from a
location in the vicinity of SW IA/NW MO early this morning to the
east into the Great Lakes by early this evening, with winds
gradually veering from northerly to east and northeasterly through
the day. The impact of the veering winds is on the current stratus.
Clouds are not clearing as quickly as anticipated and the biggest
adjustment to the forecast today is to delay the trend. Present
indications based on satellite extrapolation, NARRE-TL, and the RAP
will have the northeast-southwest oriented back edge of the clouds
located just north of St. Louis at 12z. The clearing will progress
gradually southward during the morning and may linger a bit longer
across far southern MO and southern IL due to the veering wind
profile. Meanwhile there will also be varying degrees of high
cloudiness continuing to spread into the area from the Plains in
advance of a migratory southern stream short wave trof.
With the upper level flow remaining progressive, the southern
stream trof will move into western MO towards daybreak Friday
spreading increasing clouds into the region tonight. The lower
trop high pressure system will also continue to retreat across the
Great Lakes region and into the northeast tonight. In response the
low level flow will become southwesterly above the PBL, and this
will result in moisture return and increasing low level WAA. The
greatest thrust of moisture transport will be across eastern KS
into southwest MO, however some of the guidance shows an increase
in moisture into far southeast MO as well. Combined with
steepening mid level lapse rates yields weak elevated instability,
and I have some slight chance pops moving into Reynolds County in
the predawn hours.
Glass
.LONG TERM... (Friday through Wednesday)
Issued at 343 AM CDT Thu Oct 13 2016
Overall there are less chances for precip than the forecast
indicated 2 days ago.
Friday and Friday night
Low amplitude sthrn stream trough is fcst to strengthen slightly as
it moves from the sthrn Plains to the SE US...though not sure that
will have much impact on the sensible weather in our area since the
bulk of the forcing assoc with the trough is expected to pass south
of the CWA. There will still be a chance for some light precip
across the far sthrn zones in SE MO from early mrng into early
aftn...but the threat for precip will have ended by evng. The threat
for thunder looks limited...but not nil.
Despite the clouds and potential precip...temps on Fri are expected
to be approx 5 degree warmer than Thu. Return flow warms the lower
troposphere raising the 850 temps from the mid/upper single digits C
on Thu to the lower teens by Fri. The sthrly flow continues Fri
night providing a mild night in the mid/upper 50s.
Saturday through Sunday night
The weekend will begin with a WSW oriented upper flow in the wake of
Friday`s weak sthrn stream system and will transition to a more
traditional zonal flow by Sun. There is decent agreement among the
models on the overall upper lvl pattern but do have important
differences in the details. A nthrn stream short wave will track
from the border of the US/Canadian Plains to Ontario and Quebec by
Sun. This feature will drag a cold front into the Upper Midwest on
Sat. SHRAs/TSTMs are expected top dvlp along the bndry Sat PM. Since
all the upper lvl support is in Canada, there isn`t a push to drive
the bndry south so the front hangs up along the IA/MO border late
Sat night into Sun mrng. The GFS has a weak vort max that passes
just north of the FA Sun mrng which helps explains why it shows QPF
farther south into IL and MO...co-located with the LLJ...than does
the ECMWF. Not sure this will verify but kept mentionable PoPs going
as a result. The bndry washes out Sun with sthrly flow over the
entire FA by Sun evng. The ECMWF introduces a new scenario this run
of having a sheared negatively tilted trough tracking across the
nthrn Plains into the Grt Lks Sun evng/night which drives a cold
front into the CWA late Sun night into Mon mrng. Since this is a new
solution...will not put a great deal of weight into it attm.
Temps will be warm thru the wknd. Sat will start mild and with the
aid of deep sthrly flow in advance of the nthrn stream short wave
and the approaching bndry the pressure gradient will tighten
causing winds to become gusty which will help boost temps to near
80. Sat night will be even milder than Fri night with the strong
sthrly flow continuing. Highs on Sun may be a challenge depending on
how far south the front drops before stalling and whether the GFS
solution verifies or not. Current fcst depicts that the bndry will
stall very near the nthrn FA with the bulk of whatever precip exists
Sun mrng dssptng by aftn...which means highs at least as warm as on
Sat.
Monday thru Wednesday
Upper lvl pattern starts with a low amplitude ridge over the region
emanating out of the Deep South and transitions to a broad trough
by the middle of the week. Concerning the ECMWF solution from over
the wknd...the cold front is fcst to stall near I-70 Mon and then
lift back north as a warm front Mon evng/night. Both the GFS and
ECMWF show a low amplitude nthrn stream short wave that passes along
the US/Canadian border from Mon night into Wed which will drive a
SFC low from the Plains to Quebec. Their solutions vary on timing of
the attendant cold front with the GFS clearing the bndry thru the FA
Tue night whereas the ECMWF isn`t until Wed aftn/evng. FROPA on the
GFS is dry but the ECMWF dvlps precip Wed aftn/evng across the
sthrn/ern portions of the CWA. Both models indicate a significant
trough for the end of the week...but of course there are differences
in timing and evolution.
The unseasonably warm conditions are expected to continue into early
next week with high temps in the 80s both Mon and Tue. 850 temps
warm into the mid/upper teens to near 20 for the first portion of
the week. The going fcst is conservative by holding highs in the
low/mid 80s...but eventual temps could be even higher by at least a
category. There are several variables that could hamper potential
highs in the upper 80s to near 90. Even though there isn`t a strong
signal for stratus attm...WAA low clouds/stratus could ruin the
temps fcst. The cold front the ECMWF is advertising for Mon might
cause issues as could the cold front the GFS is suggesting on Tue
though due to a strong cap with 700mb temps in the lower teens C
FROPA is fcst to be dry. Regardless...temps cool towards more
seasonal levels by the end of the week.
Miller
&&
.AVIATION... (For the 06z TAFs through 06z Thursday Night)
Issued at 1141 PM CDT Wed Oct 12 2016
MVFR ceilings will move out of the terminals from northwest to
southeast by 09Z. Otherwise dry and VFR conditions are expected
through the period with northerly winds.
SPECIFICS FOR KSTL: Current MVFR ceilings will become VFR by 09Z.
Then dry and VFR conditions are expected the rest of the period
with northerly winds.
Britt
&&
.CLIMATE...
Issued at 343 AM CDT Thu Oct 13 2016
Unseasonably warm conditions are expected to persist through
the weekend and into early next week and may approach record
territory. The following lists record high temperatures and
record high minimum temperatures for St. Louis, Columbia and
Quincy from Sunday to Tuesday.
St. LouisColumbiaQuincy
SundayHigh:89/195086/195088/1950
10/16 High Low:65/196566/196867/1968
MondayHigh:88/195089/189488/1950
10/17High Low:66/199864/196566/1935
Tuesday High:87/195386/195387/1924
10/18High Low:68/198564/197166/1938
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Nashville TN
413 AM CDT Thu Oct 13 2016
.DISCUSSION...
Do not question that the overall weather pattern will lead to some
locations receiving rainfall over the next fews days. No
indication at all that any rainfall will be heavy at any times.
No indication that marginal instability expected to develop in
the vicinity of the TN River Valley on Fri that might possibly
support the development of iso tstms would support any potential
for strong to severe tstms. There is no indication that iso to sct
tstms that could possibly develop Tue night and into Wed ahead of
a frontal system sfc/aloft would reach strong to svr thresholds
also. So, for the forecast period we have "these truths"
established.
However, quandaries abound when it comes to different model
solutions concerning specifics of areas experiencing rainfall or
not, pop forecasts for specific locations, associated cloudiness,
and along with that associated temp forecast for particular
locations, especially on Fri, where GFS MAV and NAM MET mos
disagree by more than 10 degrees on forecasted high value for
Nashville. With all of this said, have tried to lean toward a
"persistence thru the forecast distance" forecast philosophy this
morning in the suite of forecast products for the next seven day
period. Broke out a early this morning grouping in the zone
forecast product and emphasized areal coverage terms when it came
to pcpn chances, iso or sct, across mainly wrn and nrn portions of
the mid state thru the early morning hrs, as light shwrs are
continuing to move into the mid state region, associated with a
weak frontal system sfc/aloft. Short range models, including the
latest HRRR solutions,showing this activity moving ewd as the
remaining early morning hrs progress, but then dissipating during
the mid morning hrs, as sfc and upper level dynamics weaken,
washout. The establishment of zonal flow aloft as the day
progresses behind the upper level trough passage portion of this
frontal system will result in another weak upper level disturbance
moving across the mid state region Fri into the first part of Sat,
with upper level troughing dynamics becoming enhanced enough
across the above mentioned TN River Valley Region to support iso
tstm development, along with iso to sct light shwrs. Enhancing ridging
dynamics, first illustrated by the ECMWF solution, should become
established across the region Sat afternoon into Tue., before yet
another frontal system sfc/aloft moves into the mid state region
by mid week next work week.
As for temps, temps today should be at or slightly below seasonal
normal values for this time of year, as CAA associated with a
upper midwest sfc high pressure system builds into the mid state
region. Highs today will span the upper 60s northwest to upper 70s
southwest. But seasonal high temps will be short lived. The apex
of the sfc ridging influences will shift ewd with time into the
New England, setting the stage for an influx of a much warmer
western Gulf of Mexico based air mass to begin influencing the
temps across our area. Highs will climb to well above seasonal
normal values by the first part of next work week, with highs in
the mid 80s, lower 80s Cumberland Plateau Region by Tue afternoon,
in some instances, 10 to 15 degrees above seasonal normal values.
Temps are expected to slightly cool by next Wed as frontal system
approaches, with a return to seasonal normal temps not expected
until late next week behind the frontal system passage. Lows will
also be seasonable warm during most of the forecast period too,
with lows tonight spanning the low to mid 50s, warming to the low
to mid 60s, around 60 Cumberland Plateau Region by Tue morning,
before an associated cool down to more seasonable low temps is
expected also in the second half of next work week.
&&
.AVIATION...
06Z TAF DISCUSSION.
Shower activity has moved into the KCKV area, and looks to
continue to linger around for much of the overnight hours. A few
short term models have showers reaching KBNA, but keep KCSV dry.
Cold front will move through the region later this morning, and
will shift winds to be more northerly around 5 knots but up to 10
knots will be possible. Models are also continuing to indicate
MVFR cigs at KCKV and even KBNA. Current obs upstream of the mid
state do show some low MVFR cigs in the Ohio River Valley, so have
mention of MVFR cigs at KCKV later this morning. MVFR cigs will be
possible at KBNA later this afternoon as well, but kept VFR as
consensus keeps cigs higher. Models are mixed on bringing VFR
cigs back to KCKV, but for now, have VFR returning later in the
afternoon.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 72 57 76 60 80 / 20 10 40 40 20
Clarksville 68 52 72 57 79 / 20 10 50 40 10
Crossville 72 53 74 54 73 / 10 10 20 40 20
Columbia 74 56 76 58 81 / 20 10 40 40 10
Lawrenceburg 76 56 76 59 80 / 20 10 40 40 10
Waverly 68 55 72 58 79 / 20 10 50 40 10
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION......31
AVIATION........Barnwell
Area Forecast Discussion
National Weather Service Blacksburg VA
430 AM EDT Thu Oct 13 2016
.SYNOPSIS...
High pressure along the eastern sea board will shift east today as
a weak cold front drifts through the region. The front will move
south and stall from Tennessee into North Carolina tonight.
Meanwhile...an upper-level disturbance will track quickly from
the Southern Plains toward the Mid-Atlantic by Saturday. Another
weak cold front will move through the region Sunday into Monday.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 345 AM EDT Thursday...
Main focus today will be on a weak cold front, which is slated to
move quickly through the forecast area today. The supporting
positively tilted upper trough will race quickly to the northeast
leaving the front behind to stall in a west-east oriented fashion
from Tennessee into southern North Carolina by Friday.
For the past several days, the models have been indicating
potential for showers to accompany the front, mainly this morning
across the Alleghanys, dissipating fairly quickly as the activity
attempts to translate eastward across the Alleghanys and as the
upper support races off to the northeast. Latest runs of the HRRR
and the other synoptic models continue to follow suit with this
pattern. Upstream radars indicating scattered light to moderate
showers from western PA southwest into western KY and TN. See no
reason to deviate much from what the models have advertised, thus
indicating slight chance to low chance pops across the Alleghanys
tapering to below mentionable pops toward the Blue Ridge.
Overall, the antecedent air mass is fairly dry.
Upslope cloud cover will likely be fairly substantial across the
Alleghanys behind the front into the evening, before diminishing
somewhat.
Overnight, surface high pressure will slide eastward to the Mid-
Atlantic coast. Winds will come around to the northeast before
daybreak and allow moisture to begin returning to the region from
the south and southeast. Thus, while the upslope clouds will
likely begin to diminish across the Alleghanys overnight, clouds
will be on the increase in southeast upslope flow developing
across the northwest NC mountains into far southwest VA.
A fairly wide variation in temperatures is expected today with the
cold front moving through western areas during the morning with
subsequent cloud cover and gusty northwest winds holding
temperatures down in those areas. Further east, considerable
sunshine still expected and downslope winds will yield
temperatures on par to a tad warmer than what was observed
Wednesday. In addition, there is no appreciable drop in 850mb
temps until after 00Z....then falling from +12C to +15C today down
toward +8C by Friday morning. Used a blend between the cooler
ECMWF MOS and the warmer GFS MOS for max temps today.
May need to consider a frost advisory for Greenbrier and Bath
counties early Friday as temperatures dip into the mid and upper
30s in the deeper valleys with light or near calm winds.
As noted above, winds will become west to northwest and gusty
across the western mountains and toward the Blue Ridge by late
morning today, but are expected to remain well below wind
advisory criteria.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
The center of a ridge of high pressure at the surface will slowly
progress from over the spine of the Appalachians on Friday to along
the east coast by Sunday. Higher up in the atmosphere, a disturbance
is forecast to progress from the Arklatex region on Friday to across
the Tennessee and Ohio Valleys by Saturday afternoon.
Model guidance has trended drier and less organized with this
system, compared to its counterparts this time yesterday, as the
feature progresses into the high pressure over the region. Our
forecast for this time period will reflect this trend with a little
less coverage of showers in the west as compared to our previous
forecast. Most of the showers will have dissipated by Saturday
evening. A few lingering ones will still be possible across parts of
southeast West Virginia during the evening hours.
Late Saturday night into Sunday, southwest flow will increase across
the region thanks to both the high shifting farther east and the
approach of a cold front. Precipitation associated with the front
will remain west of the area during the day Sunday, but the trend
for temperatures will be higher thanks to warm air advection from
the southwest. Guidance has trended a bit slower on the arrival of
the cold front Sunday night. Our forecast has been adjusted to
confine isolated showers to the northern sections of the region
after midnight.
Temperatures will be near normal for this time of year both Friday
and Saturday. Readings on Sunday will average five to ten degrees
above normal.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
As of 400 AM EDT Thursday...
Above normal temperatures are expected during the medium range
period. Warm front continues moving north of the area Monday.
Another weak front will move into the area late Sunday into
Monday, then also return north as a warm front as a large ridge
builds aloft from the mid part of the U.S. A stronger cold front
is slated to drop southeast into the Ohio valley Tuesday night
into Wednesday.
Upper heights build across the region heading into Tuesday, then
decrease or flatten on Wednesday. Temperatures will be notably
milder at night with lows generally in the upper 40s to around 60
degrees, High temperatures will generally range from the mid 60s to
upper 70s. A few locations in southside could warm to near 80
degrees by Midweek as riding builds over the Southeast.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
As of 150 AM EDT Thursday...
A positively tilted upper trough will lift northeast across the
Great Lakes into New England today. The associated weak cold front
will move quickly through the region during the first half of the
day, then become elongated west-east by evening from TN into
northern NC. A large area of high pressure will slide eastward
across the OH Valley overnight into Friday morning.
Generally VFR skies in place ahead of the front this morning. As
the front passes the Alleghany front around daybreak, expect MVFR
cigs to develop in upslope west-northwest flow KLWB-KBLF and
potentially KBCB to a lesser extent. Generally VFR cigs are
expected to continue to the east across the Piedmont with
downslope flow developing during the morning. MVFR cigs will
likely hold into the evening/overnight hours along and near the
Alleghany front as a result of the combination of return moisture
through the TN valley on the back side of the front and continued
weak upslope flow. Generally VFR cigs expected to hold further
east.
With the front not arriving KLWB or KBCB until after daybreak and
only SCT250 in place through much of the night in advance of the
front, fog development seems likely this morning. Fog already
noted at several locations and feel that it is just a matter of
time before patchy dense fog and IFR-LIFR cigs develop, including
KBCB and KLWB. MVFR BR remains possible at KDAN and KLYH as well.
Winds mostly calm or southwest 3-5kts overnight, then becoming
WSW-WNW behind the front and increasing in speed to 8-10kts with
low end gusts mainly west of the Blue Ridge. Winds will decrease
after 00Z Fri and also begin to veer to the east fairly quickly
east of the Blue Ridge.
Medium confidence in cigs throughout the TAF valid period.
Medium confidence in vsbys through 13Z, then medium to high
confidence in vsbys through the remainder of the TAF valid period.
Medium to high confidence in wind speed/direction through the TAF
valid period.
Extended aviation discussion...
High pressure will bring mainly VFR conditions to the area Friday
into Friday night before clouds increase and the low level wedge
enhances by later Saturday as a weak disturbance passes across
from the west. This may result in sub-VFR conditions at least
across the mountains Saturday into Sunday with VFR elsewhere.
Another weak cold front to the north may bring more clouds and
showers for Monday although appears mostly VFR for now with weak
high pressure in place.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...RAB
NEAR TERM...RAB
SHORT TERM...DS
LONG TERM...KK/RAB
AVIATION...JH/PM/RAB
Area Forecast Discussion
National Weather Service Denver/Boulder CO
950 AM MDT Thu Oct 13 2016
.UPDATE...
Issued at 950 AM MDT Thu Oct 13 2016
Water vapor satellite shows drier air moving into the state from
the west on the backside of the shortwave trough. Observations and
webcams show the areas of fog over and near the South Platte River
valley has eroded. Temperatures are on their way to a warmer day.
Adjusted some sky grids and forecast to show wave clouds along the
Front Range foothills overnight. This along with a deepening
surface trough along the plains may require to warm tonight`s
forecast lows along the foothills and urban corridor.
&&
.SHORT TERM...(Today and tonight)
Issued at 310 AM MDT Thu Oct 13 2016
Dry westerly flow aloft continues over Colorado through Thursday
night with no precipitation expected area-wide and much warmer
temperatures across the Plains. The low clouds from Wednesday have
dissipated overnight. There is also a weak short wave trough
currently moving east out of Utah and into Colorado which is
generating a mid-level cloud deck. The low-level moisture is
hanging around this morning and so fog is a concern. Fog has
already developed across Weld County with Greeley reporting 1/4M
Visibility. However, surface and satellite obs combined with HRRR
and RAP model output have consistently kept the fog north of the
C-470 beltway and Denver International airport. Weld and Morgan
counties primarily will see some fog between now and a few hours
after sunrise but the fog could sneak into the northwest side of
the Denver metro area. Will continue to monitor observations for
fog advection into the metro area this morning.
During the day today temperatures rebound in a big way as the
low-level moisture is scoured out with low-level southwest flow,
and strong subsidence is parked over the state. Temperatures
across eastern Colorado should reach the mid 70s under partly
cloud skies, a 20-25 deg improvement over Wednesday. The mountains
should see similar temps compared to Wednesday with 50s and lower
60s. With much warmer 700 mb temps and continued subsidence, low
temperatures Thursday night into Friday morning will also be 10
degrees warmer across the Plains and should not see a repeat of
fog/stratus.
.LONG TERM...(Friday through Wednesday)
Issued at 310 AM MDT Thu Oct 13 2016
Height rises on Friday perpetuated by the passage of a flat
shortwave upper ridge will result in unseasonably warm
temperatures across the CWA. The presence of a low amplitude mtn
wave will further enhance warming along the Front Range with
downslope flow gradient in place. However wind speeds should not
be all that strong due to a flat pres gradient across the area.
Although the high country could see gusty west-southwest winds
developing by afternoon esply over the high ridges and peaks as a
50-70 kt mid-level speed maxima passes over Wyoming. Could see
gusts in the 30-45 mph range in the higher exposed areas. Highs
on Friday are expected to range from the low/mid 80s on the plains
to 60s and lower 70s in the mtns and high valleys. These readings
are some 12-16 deg f above average for the date. If it were not
for the light winds...the high temps...low RH and unstable bndry
layer...I would need to consider hoisting a fire weather watch
for the plains...as well as for Middle and South Parks as dry
grasses remain abundant even after chilly drippy weather
yesterday.
Saturday and Sunday...look nearly as warm and dry with the upper
ridge slowly slipping east of the area. Winds remain relatively
light except on the higher mtn ridges and peaks which protrude up
into the relatively strong zonal flow aloft. Will continue to
nudge red flag conditions at a few spots on the plains and high
valleys with low RH and warm temps...but wind speeds thankfully
will still be too weak for that.
Early part of next week...models show a buckle in the zonal flow
and a shortwave trough carving out over the northern Great Basin.
Flow aloft turns southwesterly over Colorado and temps aloft begin
to cool. Models also show moistening across the nwrn corner of
the state on Monday...with further moistening and cooling over
the northwest corner of the CWA by Monday night and Tuesday. Low
pops seem in order across this part of the CWA with precip
starting out as rain. As temps cool should see the snow level
leveling to around 9500 ft in the nrn mtns late Monday night and
Tuesday morning. But any snow accumulation should be spotty and
minuscule. While areas east of the mtns should remain dry...although
some of the models notably the ECMWF indicate spotty light QPF
over northern portions of the plains Tuesday aftn and overnight.
The GFS and DGEX indicate nothing. By Wednesday all models show
amplification of the upper trough now just east of Colorado which
places the CWA under a cooler and stronger northwest flow regime.
It`s a bit too early to know if we`ll see measurable precip with
the upslope flow models suggest on Wednesday. Will hold off
mentioning any east of the mtns for now. But it should turn
cooler Wednesday and Thursday.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 950 AM MDT Thu Oct 13 2016
VFR conditions expected through Friday afternoon. Current southwesterly
drainage winds should should slowly swing through the northwest until
mid- day before going light northeasterly, then back to an
enhanced drainage overnight as a surface trough deepens over the
plains.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Kriederman
SHORT TERM...Schlatter
LONG TERM...Baker
AVIATION...Kriederman
Area Forecast Discussion
National Weather Service State College PA
1112 AM EDT Thu Oct 13 2016
.SYNOPSIS...
A cold front will pass through the commonwealth through this
afternoon. High pressure will move back in for Friday and
Saturday with fair weather and cool nights, but daytime
temperatures returning to above normal.
&&
.NEAR TERM /THROUGH TONIGHT/...
Broken line of showers traversing central PA at late morning.
HRRR handling character and timing well...with most of central and
western portions remaining dry from here on out. Band of showers
will cross through and exit the east by 18z...similar to previous
thinking.
Adjusted POPs downward behind FROPA and maintained the gusty post
frontal depiction...as upstream METAR gusts suggest slightly
higher than guidance winds/gusts favored this afternoon.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
Cross-lake flow will make a few lake effect clouds in the evening,
but it should clear out completely early tonight. A light
gradient wind will be left for at least the first half if not all
of the night in the southeast where the growing season is on-
going. The wind will be just about the only factor preventing a
frost in those locations. The clear skies will help temps drop
into the m30s-l40s there. Northern and western locations will drop
below freezing tonight, but we probably do not need to mention
frost since the growing season is over there. Will just mention to
next shift for possible mentions/advy if it looks like it will be
more- calm than it looks at this point.
High pressure moving in will ensure that Friday will feature
abundant sunshine and a light N/NE wind. Maxes will be a few
degrees below normals, but the sun should make it feel milder.
Friday night/Sat AM is the most interesting period in the short
term as the high should be overhead. Temps will likely get cold
enough and wind will be light enough to allow a widespread frost
in the SErn half where the growing season continues. Have
continued the mention of frost for Sat AM in the HWO, but it is
far too early for an advy - esp if we need to consider one for
tonight. Would not be surprised to see THV and SEG get down to
freezing. But these outliers will not be enough to make me think
a freeze watch is necessary.
Saturday will be another sunny and mild day. Temps will get 3-5F
warmer than Friday over most of the area - with the NW as much as
10F warmer.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
A frontal system accompanied by a band of showers will reach the
area late Sunday into Sunday night, with enough agreement and
ensemble support likely POPs over the northwest half of the CWA.
Rainfall amounts should be <0.50 inch.
The pattern looks somewhat unsettled heading into next week as
the area remains within fast quasi-zonal flow downstream of mean
western trough and north of upper ridge over the northern GOMEX.
Any shower activity would likely be periodic on the light side.
There is better than average confidence with respect to temps
which should trend milder and average above climatological normals
into the second half of the month.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
Cold front with accompanying MVFR cigs and shra pushing through
Middle to Lower Susq River Valley through 18z. Post frontal NW
flow and sfc wnd g25kt expected behind this front.
Local IFR cigs at KJST will subside by 1630z as drier
northwesterlies arrive. For the Lower Susq River Valley...high
MVFR cigs will accompany frontal passage during the late morning
and early afternoon. The arrival of drier air is likely to result
in a return to widespread VFR conditions beginning late this
afternoon.
Outlook...
Fri...AM fog possible, esp KBFD.
Sat...No sig wx expected.
Sun...PM showers cig reductions possible north.
Mon...Showers cig reductions possible, mainly north.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Dangelo/DeVoir
NEAR TERM...Dangelo/DeVoir
SHORT TERM...Dangelo
LONG TERM...Steinbugl
AVIATION...Fitzgerald/DeVoir
Area Forecast Discussion
National Weather Service Key West FL
1034 AM EDT Thu Oct 13 2016
.DISCUSSION...
An early morning loop of the KBYX radar shows several areas of light
rains and showers moving southwestward along the Keys island chain
and mainly to the south across the Straits of Florida. Winds are
fresh to occasionally strong from the northeast. Under partly to
mostly cloudy skies, temperatures are in the lower 80s.
The early morning local sounding indicated a continued veering of the
wind profile through about 20000 feet. Moisture has increased by over
one half an inch, with a precipitable water value now at 1.9 inches.
Instability has increased and the previously strong inversion has
eroded significantly and lifted, leaving a remnant shallow
convectively resistant layer based near 12000 feet. Updated the zone
forecast this morning to include a breezy descriptor and nudge our
advertised winds a little based on the latest observations and the
low level winds sampled through the lowest layers from our morning
sounding...and of course the latest available ASCAT pass.
&&
.MARINE...
Expanded the small craft advisory to include the Straits of Florida
beyond the 20 nm mile mark from the Keys island chain. That was based
on the latest available ASCAT pass, available obs across our marine
zones, and the latest update of the HRRR locally. Thus, all near and
offshore waters surrounding the Florida Keys now have an advisory for
small craft headlined, including Florida Bay.
&&
.AVIATION...
VFR with sporadic MVFR is expected as a weak disturbance provides a
focus for scattered showers and occasional lowering cigs/vis across
the island chain. Amendments will be issued as necessary. Brisk
northeast flow will continue with gusts near 20 kts until 00z.
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...None.
GM...Small Craft Advisory GMZ031>035-042>044-052>055-072>075.
&&
$$
Public/Marine/Fire...04
Aviation/Nowcasts....MCLOVIN
Data Collection......Vickery
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Area Forecast Discussion
National Weather Service Louisville KY
1114 AM EDT Thu Oct 13 2016
...Forecast Update...
Issued at 1110 AM EDT Thu Oct 13 2016
Updated the forecast to adjust POPs and temps. Except for a few very
light showers/sprinkles across central KY, the main precip has ended
across the region. Extensive low level clouds stretching back into
central IN should stick with us through mid afternoon before finally
beginning to break up over southern IN first toward mid-late
afternoon and central/southern KY toward late afternoon/evening.
These clouds will help limit high temps to the low to mid 60s today
which is a few degrees cooler than previously forecast.
Issued at 400 AM EDT Thu Oct 13 2016
We are reminded that weather is a very humbling field... as we`ve
been watching the puny precipitation pattern all night long, waining
through 320 AM. In the last 30 minutes or so, the LLJ and some warm
advection has increased the activity across the southern tier. All
night long, the models had been trying to paint a picture of
increasing POPs and the HRRR had been advertising it since 4Z, and
alas, by 730Z it`s coming to fruition across the southern areas.
We just updated the POP and WX grids to account for 40% POPs for
showers from Ohio County through Barren and over to the southern
Bluegrass counties between 9-13Z. Update will be coming soon.
.SHORT TERM (Now through Friday)...
Issued at 253 AM EDT Thu Oct 13 2016
Today and Tonight...
Early this morning, a cold front extends from TOL to IND to near
PAH. Scattered showers out ahead of this have fizzled out as they
approach Kentucky, but a stray shower is not out of the question
especially across central and southern parts of the CWA. Cloud cover
and much cooler temperatures will be the main event across the
region today as overcast to mostly cloudy conditions will prevail
into the mid afternoon. The back edge of the cloud cover is
currently situated near DBQ to UIN and will be slow to reach our
area due to ample moisture before drier air moves in late in the day
and into Friday.
Temperatures today will remain in the mid 60s for much of the area,
with slightly warmer readings south, but breaking into the 70s will
be a struggle thanks to the cloud cover. In fact, it is very likely
that we have already seen our 24 hour high for today. The 1000-850mb
thickness values drop significantly behind the front with decent
cold advection. Skies will begin clearing from northwest to
southeast around 19-21Z as cool Canadian high pressure moves in.
This will allow temperatures overnight to fall into the upper 40s in
the Bluegrass and low to mid 50s for points south. A few readings
closer to 40 are possible north of I 64, such as FFT, Lexington
IN, and Cynthiana.
Friday...
The main story for Friday is the cloud cover moving ahead of the srn
stream system moving out of TX into the Ozarks. The timing of the
cloud cover will have a profound affect on high temps. If the mid
and high clouds move in quicker temps may not get out of the 60s.
For now, made a minor downward tweak in max temps.
.LONG TERM (Friday Night through Wednesday)...
Issued at 245 AM EDT Thu Oct 13 2016
...Couple of weak systems Fri Ngt and Sunday...
...Major warm up next week...
1st System...
Well...the pattern starts off zonal with a weak system pushing out
of the Land of Enchantment and the Lone Star State towards the CWA.
The models moisture availability lift are marginal and will keep the
theme of chc pops, with not enough instability to warrant TSRA and
keep the most prominent pops south of I 64, and highest S of BG
Parkways for Friday night into mid morning Sat. Cloud cover will
take its time to depart Saturday, especially over the Bluegrass.
Could be a 5-10 degree temperature spread from Richmond/LEX/
Winchester in the cloud cover Saturday to Rough River/Beaver Dam/BWG
where the sunshine will be.
2nd System...
The next feature is a cold front from the northwest which will be
juxtapositioned from Hudson Bay to ORD to STL Sunday sunrise. This
is slated to drop into Indiana Sunday afternoon through Monday and
have difficulties pushing very far south. As the front approaches,
it becomes orientated west-east and stall out north of the Ohio
River. This is where the highest chances of showers will be found.
There is some limited instability with this and will keep the slgt
chance TSRA. The POP gradient will be stout, with the emphasis N of
I 64.
The major story of the entire forecast is the herculean ridge
developing over TX and moving into the heart of Dixie. The 592 m
high will bring very warm temps to the Mid and Deep South Mon-Wed.
H9 and H8 temps are 1-2 standard deviations above normal and will
bring temps into at least mid 80s and with the very dry vegetation,
upper 80s are plausible.
Beyond that, model guidance suggests another cold front will be
moving into the Ohio Valley in the Wed-Thu timeframe, but timing and
strength differences between the various deterministic and ensemble
guidance lowers confidence. A model consensus approach puts slight
chances across most of the area.
&&
.AVIATION (12Z TAF Update)...
Issued at 645 AM EDT Thu Oct 13 2016
Cold front continues to make slow progress across Kentucky, and
while precip did finally blossom ahead of it, only BWG is affected
in this issuance. Otherwise north winds and stratus will rule the
day as high pressure tries to build in, with partial clearing around
sunset.
For SDF: Post-frontal wind surge ongoing, so may keep north winds
around 10 kt for the morning. Fuel-alternate ceilings will lift to
high-end MVFR early in the afternoon, and finally scatter out around
sunset. Any increase in clouds Fri should hold off beyond the
planning period.
For LEX: MVFR ceilings initially will drop below fuel-alternate by
mid-morning, likely accompanied by a slight surge as winds shift due
north. Shallow boundary layer should keep speeds near 10 kt without
any gusts. Similar lifting and scattering trend in the ceilings to
SDF, give or take an hour or two.
For BWG: Will initialize with VCSH and fuel-alternate MVFR, but
include a TEMPO for SHRA and IFR ceilings through mid-morning.
Closer proximity to the front will limit the wind speeds and delay
any improvement in ceilings until mid-afternoon. Could remain MVFR
through the valid TAF period, but at this point will opt for a
borderline MVFR/VFR ceiling. Guidance hinting at fog toward daybreak
Fri, but for now expect the stratus to win out.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........AMS
Short Term.....JDG
Long Term......JDG
Aviation.......RAS
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
637 AM CDT THU OCT 13 2016
.SHORT TERM... (Through Late Tonight)
Issued at 343 AM CDT Thu Oct 13 2016
A seasonably cool day is expected as expansive surface high pressure
dominates the area. The high pressure center will shift from a
location in the vicinity of SW IA/NW MO early this morning to the
east into the Great Lakes by early this evening, with winds
gradually veering from northerly to east and northeasterly through
the day. The impact of the veering winds is on the current stratus.
Clouds are not clearing as quickly as anticipated and the biggest
adjustment to the forecast today is to delay the trend. Present
indications based on satellite extrapolation, NARRE-TL, and the RAP
will have the northeast-southwest oriented back edge of the clouds
located just north of St. Louis at 12z. The clearing will progress
gradually southward during the morning and may linger a bit longer
across far southern MO and southern IL due to the veering wind
profile. Meanwhile there will also be varying degrees of high
cloudiness continuing to spread into the area from the Plains in
advance of a migratory southern stream short wave trof.
With the upper level flow remaining progressive, the southern
stream trof will move into western MO towards daybreak Friday
spreading increasing clouds into the region tonight. The lower
trop high pressure system will also continue to retreat across the
Great Lakes region and into the northeast tonight. In response the
low level flow will become southwesterly above the PBL, and this
will result in moisture return and increasing low level WAA. The
greatest thrust of moisture transport will be across eastern KS
into southwest MO, however some of the guidance shows an increase
in moisture into far southeast MO as well. Combined with
steepening mid level lapse rates yields weak elevated instability,
and I have some slight chance pops moving into Reynolds County in
the predawn hours.
Glass
.LONG TERM... (Friday through Wednesday)
Issued at 343 AM CDT Thu Oct 13 2016
Overall there are less chances for precip than the forecast
indicated 2 days ago.
Friday and Friday night
Low amplitude sthrn stream trough is fcst to strengthen slightly as
it moves from the sthrn Plains to the SE US...though not sure that
will have much impact on the sensible weather in our area since the
bulk of the forcing assoc with the trough is expected to pass south
of the CWA. There will still be a chance for some light precip
across the far sthrn zones in SE MO from early mrng into early
aftn...but the threat for precip will have ended by evng. The threat
for thunder looks limited...but not nil.
Despite the clouds and potential precip...temps on Fri are expected
to be approx 5 degree warmer than Thu. Return flow warms the lower
troposphere raising the 850 temps from the mid/upper single digits C
on Thu to the lower teens by Fri. The sthrly flow continues Fri
night providing a mild night in the mid/upper 50s.
Saturday through Sunday night
The weekend will begin with a WSW oriented upper flow in the wake of
Friday`s weak sthrn stream system and will transition to a more
traditional zonal flow by Sun. There is decent agreement among the
models on the overall upper lvl pattern but do have important
differences in the details. A nthrn stream short wave will track
from the border of the US/Canadian Plains to Ontario and Quebec by
Sun. This feature will drag a cold front into the Upper Midwest on
Sat. SHRAs/TSTMs are expected top dvlp along the bndry Sat PM. Since
all the upper lvl support is in Canada, there isn`t a push to drive
the bndry south so the front hangs up along the IA/MO border late
Sat night into Sun mrng. The GFS has a weak vort max that passes
just north of the FA Sun mrng which helps explains why it shows QPF
farther south into IL and MO...co-located with the LLJ...than does
the ECMWF. Not sure this will verify but kept mentionable PoPs going
as a result. The bndry washes out Sun with sthrly flow over the
entire FA by Sun evng. The ECMWF introduces a new scenario this run
of having a sheared negatively tilted trough tracking across the
nthrn Plains into the Grt Lks Sun evng/night which drives a cold
front into the CWA late Sun night into Mon mrng. Since this is a new
solution...will not put a great deal of weight into it attm.
Temps will be warm thru the wknd. Sat will start mild and with the
aid of deep sthrly flow in advance of the nthrn stream short wave
and the approaching bndry the pressure gradient will tighten
causing winds to become gusty which will help boost temps to near
80. Sat night will be even milder than Fri night with the strong
sthrly flow continuing. Highs on Sun may be a challenge depending on
how far south the front drops before stalling and whether the GFS
solution verifies or not. Current fcst depicts that the bndry will
stall very near the nthrn FA with the bulk of whatever precip exists
Sun mrng dssptng by aftn...which means highs at least as warm as on
Sat.
Monday thru Wednesday
Upper lvl pattern starts with a low amplitude ridge over the region
emanating out of the Deep South and transitions to a broad trough
by the middle of the week. Concerning the ECMWF solution from over
the wknd...the cold front is fcst to stall near I-70 Mon and then
lift back north as a warm front Mon evng/night. Both the GFS and
ECMWF show a low amplitude nthrn stream short wave that passes along
the US/Canadian border from Mon night into Wed which will drive a
SFC low from the Plains to Quebec. Their solutions vary on timing of
the attendant cold front with the GFS clearing the bndry thru the FA
Tue night whereas the ECMWF isn`t until Wed aftn/evng. FROPA on the
GFS is dry but the ECMWF dvlps precip Wed aftn/evng across the
sthrn/ern portions of the CWA. Both models indicate a significant
trough for the end of the week...but of course there are differences
in timing and evolution.
The unseasonably warm conditions are expected to continue into early
next week with high temps in the 80s both Mon and Tue. 850 temps
warm into the mid/upper teens to near 20 for the first portion of
the week. The going fcst is conservative by holding highs in the
low/mid 80s...but eventual temps could be even higher by at least a
category. There are several variables that could hamper potential
highs in the upper 80s to near 90. Even though there isn`t a strong
signal for stratus attm...WAA low clouds/stratus could ruin the
temps fcst. The cold front the ECMWF is advertising for Mon might
cause issues as could the cold front the GFS is suggesting on Tue
though due to a strong cap with 700mb temps in the lower teens C
FROPA is fcst to be dry. Regardless...temps cool towards more
seasonal levels by the end of the week.
Miller
&&
.AVIATION... (For the 12z TAFs through 12z Friday Morning)
Issued at 624 AM CDT Thu Oct 13 2016
VFR flight conditions are expected at KUIN and KCOU through the
forecast period.
MVFR Cigs/Stratus across eastern MO and the southern half of IL
have been much slower to clear than earlier projected. Present
trends suggest that clearing across the St. Louis region should be
in the 15-16z time frame. Thereafter VFR flight conditions will
prevail through the remainder of the forecast period.
SPECIFICS FOR KSTL:
MVFR Cigs/Stratus has been much slower to clear than earlier projected.
Present trends suggest clearing at KSTL around 15z. Thereafter
VFR flight conditions will prevail through the remainder of the
forecast period.
Glass
&&
.CLIMATE...
Issued at 343 AM CDT Thu Oct 13 2016
Unseasonably warm conditions are expected to persist through
the weekend and into early next week and may approach record
territory. The following lists record high temperatures and
record high minimum temperatures for St. Louis, Columbia and
Quincy from Sunday to Tuesday.
St. LouisColumbiaQuincy
SundayHigh:89/195086/195088/1950
10/16 High Low:65/196566/196867/1968
MondayHigh:88/195089/189488/1950
10/17High Low:66/199864/196566/1935
Tuesday High:87/195386/195387/1924
10/18High Low:68/198564/197166/1938
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Nashville TN
613 AM CDT Thu Oct 13 2016
.UPDATE...
FOR 12Z AVIATION DISCUSSION.
&&
.DISCUSSION...
Do not question that the overall weather pattern will lead to some
locations receiving rainfall over the next fews days. No
indication at all that any rainfall will be heavy at any times.
No indication that marginal instability expected to develop in
the vicinity of the TN River Valley on Fri that might possibly
support the development of iso tstms would support any potential
for strong to severe tstms. There is no indication that iso to sct
tstms that could possibly develop Tue night and into Wed ahead of
a frontal system sfc/aloft would reach strong to svr thresholds
also. So, for the forecast period we have "these truths"
established.
However, quandaries abound when it comes to different model
solutions concerning specifics of areas experiencing rainfall or
not, pop forecasts for specific locations, associated cloudiness,
and along with that associated temp forecast for particular
locations, especially on Fri, where GFS MAV and NAM MET mos
disagree by more than 10 degrees on forecasted high value for
Nashville. With all of this said, have tried to lean toward a
"persistence thru the forecast distance" forecast philosophy this
morning in the suite of forecast products for the next seven day
period. Broke out a early this morning grouping in the zone
forecast product and emphasized areal coverage terms when it came
to pcpn chances, iso or sct, across mainly wrn and nrn portions of
the mid state thru the early morning hrs, as light shwrs are
continuing to move into the mid state region, associated with a
weak frontal system sfc/aloft. Short range models, including the
latest HRRR solutions,showing this activity moving ewd as the
remaining early morning hrs progress, but then dissipating during
the mid morning hrs, as sfc and upper level dynamics weaken,
washout. The establishment of zonal flow aloft as the day
progresses behind the upper level trough passage portion of this
frontal system will result in another weak upper level disturbance
moving across the mid state region Fri into the first part of Sat,
with upper level troughing dynamics becoming enhanced enough
across the above mentioned TN River Valley Region to support iso
tstm development, along with iso to sct light shwrs. Enhancing ridging
dynamics, first illustrated by the ECMWF solution, should become
established across the region Sat afternoon into Tue., before yet
another frontal system sfc/aloft moves into the mid state region
by mid week next work week.
As for temps, temps today should be at or slightly below seasonal
normal values for this time of year, as CAA associated with a
upper midwest sfc high pressure system builds into the mid state
region. Highs today will span the upper 60s northwest to upper 70s
southwest. But seasonal high temps will be short lived. The apex
of the sfc ridging influences will shift ewd with time into the
New England, setting the stage for an influx of a much warmer
western Gulf of Mexico based air mass to begin influencing the
temps across our area. Highs will climb to well above seasonal
normal values by the first part of next work week, with highs in
the mid 80s, lower 80s Cumberland Plateau Region by Tue afternoon,
in some instances, 10 to 15 degrees above seasonal normal values.
Temps are expected to slightly cool by next Wed as frontal system
approaches, with a return to seasonal normal temps not expected
until late next week behind the frontal system passage. Lows will
also be seasonable warm during most of the forecast period too,
with lows tonight spanning the low to mid 50s, warming to the low
to mid 60s, around 60 Cumberland Plateau Region by Tue morning,
before an associated cool down to more seasonable low temps is
expected also in the second half of next work week.
&&
.AVIATION...
12Z TAF DISCUSSION.
Reduced flight categories are slowly filtering into the mid-state
this morning. Mostly MVFR, but a small period of IFR is expected
this morning for KCKV/KBNA. By this afternoon, while a cloud deck
will persist, VFR is likely for all 3 terminals. Winds will be
light as the shift to the north with the frontal passage today.
Decreased cigs and vis are likely again tonight. Mostly MVFR but
some IFR is possible after 06Z tonight. Winds will remain light.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION......31
AVIATION........Unger
Area Forecast Discussion
National Weather Service Pendleton OR
824 AM PDT THU OCT 13 2016
.UPDATE...Active weather pattern for the next several days with
multiple storm systems expected to impact the region. Widespread
rain will affect the area this afternoon but the big forecast
challenge will be with the winds and how much of the strong winds
aloft will mix down to the surface. Currently numerous wind
advisories and one wind warning are in effect. The latest HRRR
suggests that peak wind gusts above 50 kt will be fairly widespread
this evening. As of now the best potential for strong winds outside
of our current highlights looks to be along the east slopes of the
Oregon Cascades and will be monitoring for a potential High Wind
Warning during the day today. 78
&&
.PREV DISCUSSION... /issued 320 AM PDT THU OCT 13 2016/
SHORT TERM...Today through Saturday afternoon...A warm front will
bring rain to the region today. snow levels will be rising from 8000
to 9000 feet by this afternoon. KPDT radar was showing rain
already moving across Kittitas, Yakima and Klickitat Counties early
this morning with surface observations reporting a few hundredths
of an inch of rain. A low developing just offshore will tighten
pressure gradients east of the Cascades for breezy to windy
conditions. A wind advisory is in effect for Central and North
Central Oregon, the northern Blue Mountain Foothills of Oregon, the
Blue Mountain Foothills of Washington, as well as the Lower columbia
Basin of both States and the Kittitas and Yakima Valleys. A high
wind warning is in effect for possible strong winds along the
Southern Blue Mountain Foothills of Oregon beginning late this
afternoon and continuing through this evening.
A cold front will move across the forecast area tonight for more
rain with rain ending before daybreak in the Lower Columbia Basin,
the Yakima Valley and North Central Oregon. Otherwise, a moist
southwest flow aloft will remain over the region through Friday for
rain showers in the eastern mountains and along the east slopes of
the Washington and Oregon Cascades. Lower elevations will be rain
shadowed through the day on Friday. Then on Saturday another low
pressure system develops in the near waters just offshore and will
push a cold front with attendant rain into the forecast area. Snow
levels on Saturday will be around 6000 to 7000 feet. Polan
LONG TERM...Saturday night through Wednesday. Extended models
remain in good agreement with an active weather pattern for the
Pacific northwest. A strong upper level jet stream will generate
several lows which will move into southern BC or the Pacific
northwest. The most significant will be a deep surface low pressure
system tracking into western Washington/Vancouver island late Sat.
This will likely produce very windy conditions across the forecast
area. For Sunday through Wednesday additional systems will move
across the region with periods of rain and wind. Snow levels will be
5-7k feet. Rainfall amounts of 1-3 inches expected for the
mountains. 94
AVIATION...12z tafs. Ceilings 060-120 early this morning lowering
to 030-070 with rain developing. The rain will taper off late
evening after a cold frontal passage. Winds will be increasing
becoming 10-20kt by late morning and 15-30kt from afternoon through
the overnight. 94
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 61 50 66 48 / 80 60 10 30
ALW 62 54 66 52 / 90 90 10 30
PSC 62 54 68 51 / 80 80 10 20
YKM 59 47 67 44 / 90 80 10 20
HRI 63 51 68 48 / 70 60 10 20
ELN 55 43 62 42 / 90 90 10 30
RDM 65 44 62 43 / 80 70 10 30
LGD 58 47 61 44 / 90 80 30 40
GCD 57 48 60 45 / 90 90 30 40
DLS 64 52 67 50 / 100 80 10 40
&&
.PDT Watches/Warnings/Advisories...
OR...High Wind Warning from 4 PM this afternoon to 10 PM PDT this
evening for ORZ508.
Wind Advisory from 6 PM this evening to 6 PM PDT Friday for
ORZ507.
Wind Advisory from 10 AM to 6 PM PDT Friday for ORZ044.
Wind Advisory from 3 PM this afternoon to 3 PM PDT Friday for
ORZ511.
Wind Advisory from 6 PM this evening to 3 PM PDT Friday for
ORZ510.
Wind Advisory from 10 PM this evening to 6 PM PDT Friday for
ORZ508.
Wind Advisory from 2 PM this afternoon to 4 AM PDT Friday for
ORZ049.
WA...Wind Advisory from 10 AM to 6 PM PDT Friday for WAZ028-029.
&&
$$
78
Area Forecast Discussion
National Weather Service Blacksburg VA
748 AM EDT Thu Oct 13 2016
.SYNOPSIS...
High pressure along the eastern sea board will shift east today as
a weak cold front drifts through the region. The front will move
south and stall from Tennessee into North Carolina tonight.
Meanwhile...an upper-level disturbance will track quickly from
the Southern Plains toward the Mid-Atlantic by Saturday. Another
weak cold front will move through the region Sunday into Monday.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 345 AM EDT Thursday...
Main focus today will be on a weak cold front, which is slated to
move quickly through the forecast area today. The supporting
positively tilted upper trough will race quickly to the northeast
leaving the front behind to stall in a west-east oriented fashion
from Tennessee into southern North Carolina by Friday.
For the past several days, the models have been indicating
potential for showers to accompany the front, mainly this morning
across the Alleghanys, dissipating fairly quickly as the activity
attempts to translate eastward across the Alleghanys and as the
upper support races off to the northeast. Latest runs of the HRRR
and the other synoptic models continue to follow suit with this
pattern. Upstream radars indicating scattered light to moderate
showers from western PA southwest into western KY and TN. See no
reason to deviate much from what the models have advertised, thus
indicating slight chance to low chance pops across the Alleghanys
tapering to below mentionable pops toward the Blue Ridge.
Overall, the antecedent air mass is fairly dry.
Upslope cloud cover will likely be fairly substantial across the
Alleghanys behind the front into the evening, before diminishing
somewhat.
Overnight, surface high pressure will slide eastward to the Mid-
Atlantic coast. Winds will come around to the northeast before
daybreak and allow moisture to begin returning to the region from
the south and southeast. Thus, while the upslope clouds will
likely begin to diminish across the Alleghanys overnight, clouds
will be on the increase in southeast upslope flow developing
across the northwest NC mountains into far southwest VA.
A fairly wide variation in temperatures is expected today with the
cold front moving through western areas during the morning with
subsequent cloud cover and gusty northwest winds holding
temperatures down in those areas. Further east, considerable
sunshine still expected and downslope winds will yield
temperatures on par to a tad warmer than what was observed
Wednesday. In addition, there is no appreciable drop in 850mb
temps until after 00Z....then falling from +12C to +15C today down
toward +8C by Friday morning. Used a blend between the cooler
ECMWF MOS and the warmer GFS MOS for max temps today.
May need to consider a frost advisory for Greenbrier and Bath
counties early Friday as temperatures dip into the mid and upper
30s in the deeper valleys with light or near calm winds.
As noted above, winds will become west to northwest and gusty
across the western mountains and toward the Blue Ridge by late
morning today, but are expected to remain well below wind
advisory criteria.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
The center of a ridge of high pressure at the surface will slowly
progress from over the spine of the Appalachians on Friday to along
the east coast by Sunday. Higher up in the atmosphere, a disturbance
is forecast to progress from the Arklatex region on Friday to across
the Tennessee and Ohio Valleys by Saturday afternoon.
Model guidance has trended drier and less organized with this
system, compared to its counterparts this time yesterday, as the
feature progresses into the high pressure over the region. Our
forecast for this time period will reflect this trend with a little
less coverage of showers in the west as compared to our previous
forecast. Most of the showers will have dissipated by Saturday
evening. A few lingering ones will still be possible across parts of
southeast West Virginia during the evening hours.
Late Saturday night into Sunday, southwest flow will increase across
the region thanks to both the high shifting farther east and the
approach of a cold front. Precipitation associated with the front
will remain west of the area during the day Sunday, but the trend
for temperatures will be higher thanks to warm air advection from
the southwest. Guidance has trended a bit slower on the arrival of
the cold front Sunday night. Our forecast has been adjusted to
confine isolated showers to the northern sections of the region
after midnight.
Temperatures will be near normal for this time of year both Friday
and Saturday. Readings on Sunday will average five to ten degrees
above normal.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
As of 400 AM EDT Thursday...
Above normal temperatures are expected during the medium range
period. Warm front continues moving north of the area Monday.
Another weak front will move into the area late Sunday into
Monday, then also return north as a warm front as a large ridge
builds aloft from the mid part of the U.S. A stronger cold front
is slated to drop southeast into the Ohio valley Tuesday night
into Wednesday.
Upper heights build across the region heading into Tuesday, then
decrease or flatten on Wednesday. Temperatures will be notably
milder at night with lows generally in the upper 40s to around 60
degrees, High temperatures will generally range from the mid 60s to
upper 70s. A few locations in southside could warm to near 80
degrees by Midweek as riding builds over the Southeast.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
As of 745 AM EDT Thursday...
A positively tilted upper trough will lift northeast across the
Great Lakes into New England today. The associated weak cold front
will move quickly through the region during the first half of the
day, then become elongated west-east by evening from TN into
northern NC. A large area of high pressure will slide eastward
across the OH Valley overnight into Friday morning.
Mid and high clouds are on the increase from the west. Cigs so far
are mostly VFR, but expect MVFR cigs to evolve by mid-morning west
of the Blue Ridge, especially across the Alleghanys. A few showers
may drift into the Alleghanys before dissipating as the upper
support races off to the northeast and downslope drying takes
place to the east toward the Piedmont. Cigs east of the Alleghany
front are largely expected to remain VFR through the TAF valid
period, but periods of BKN low end VFR cigs possible through the
early-mid afternoon behind the front.
Patchy dense fog mainly impacting KBCB this morning with LIFR
cigs/vsbys. This will dissipate quickly by 13Z.
Overnight into Friday morning, a large area of high pressure will
build over the region and shift fairly quickly to the northern
Mid-Atlantic coast. This will cause winds to veer to the northeast
after 04Z in most areas. Return moisture not expected to ensue to
any significance at the TAF sites, possibly across northwest
NC/far southwest VA. Low clouds/ceilings eastern WV will dissipate
after 00Z as the upslope ends. Therefore, mainly VFR all areas
overnight until patchy dense fog develops again early Friday
morning at the usual spots, KBCB, KLWB, etc.
Winds becoming WSW-WNW behind the front and increasing in speed
to 8-10kts with low end gusts mainly west of the Blue Ridge. Winds
will decrease after 00Z Fri and also begin to veer to the east
fairly quickly east of the Blue Ridge.
Medium confidence in cigs throughout the TAF valid period.
Medium confidence in vsbys through 13Z, then medium to high
confidence in vsbys through the remainder of the TAF valid period.
Medium to high confidence in wind speed/direction through the TAF
valid period.
Extended aviation discussion...
High pressure will bring mainly VFR conditions to the area Friday
into Friday night before clouds increase and the low level wedge
enhances by later Saturday as a weak disturbance passes across
from the west. This may result in sub-VFR conditions at least
across the mountains Saturday into Sunday with VFR elsewhere.
Another weak cold front to the north may bring more clouds and
showers for Monday although appears mostly VFR for now with weak
high pressure in place.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...RAB
NEAR TERM...RAB
SHORT TERM...DS
LONG TERM...KK/RAB
AVIATION...RAB
Area Forecast Discussion
National Weather Service SAN ANGELO TX
615 AM CDT THU OCT 13 2016
.AVIATION...
/12Z TAFS/
MVFR cigs have spread across all of the West Central Texas
terminals early this morning. These should persist in all areas
for at least the morning hours, but latest HRRR show some breaking
up of the lowest clouds by early afternoon, especially across the
southern locations. Complicating the process will be the presence
of mid and high clouds as well, so trying to pin down the timing
of when the MVFR cigs may become VFR will be an uncertain
forecast. Have shown most areas going VFR during the afternoon,
but this timing will likely need to be adjusted through the day.
&&
.PREV DISCUSSION... /issued 412 AM CDT THU OCT 13 2016/
SHORT TERM...
(Today and Tonight)
Cold front has sagged just south of the area early this morning,
with all observations showing a light north wind. Do not expect the
front to sag much farther south and will soon begin to dissipate. As
hinted at yesterday, low clouds are filling in from the north,
covering much of the Big Country as of 3 AM. These low clouds should
cover much of the area by shortly after sunrise, and persist through
the morning. Just how long they hold into the afternoon will be a
key to the forecast, but expect at least a decent coverage of low
clouds to eventually have mid and high clouds developing over the
top. With this in mind, lowered afternoon highs just a couple more
degrees, with highs in the upper 60s across the I-20 corridor to mid
70s across the I-10 areas.
Potent shortwave across the Four-Corners area noted on water vapor
this morning, moving east. Most of this energy will pass across the
Panhandle and Oklahoma, but a little lift from the wave and some
weak isentropic lift over the wakening frontal boundary should
combine to produce a few showers and storms across the area. Best
chance will be across the far north across Haskell and Throckmorton
Counties.
LONG TERM...
(Friday through Wednesday)
Upper shortwave will be exiting east Friday morning, along with
rain chances. Keeping a slight chance of showers and isolated
thunderstorms over the the Big Country during the morning Friday,
with the best potential north and east of Abilene. Temperatures
will be warming into the lower and mid 80s Friday, with return of
south winds and subsidence behind the upper shortwave.
Warm conditions will continue into the middle of next week with a
lee trough in place and upper ridging in place. Highs are expected
in the lower 90s and lows in the 60s. A cold front is possible
Wednesday which would cool temperatures, with highs in the upper
70s north to mid 80s along the I-10 corridor. The ECMWF is
indicating a few showers or thunderstorms Wednesday night
along/east of an Abilene to Junction line as the front moves
through, but this is just beyond the 7 day forecast.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 69 60 83 67 / 20 40 20 5
San Angelo 73 62 86 66 / 10 20 10 5
Junction 76 64 85 66 / 20 20 10 5
Brownwood 73 61 84 66 / 10 30 20 5
Sweetwater 67 60 83 66 / 20 30 10 5
Ozona 75 65 83 65 / 20 20 10 5
&&
.SJT Watches/Warnings/Advisories...
None.
&&
$$
07/99/99
Area Forecast Discussion
National Weather Service Billings MT
401 PM MDT Thu Oct 13 2016
.SHORT TERM...valid for Tdy and Fri...
Powerful jet stream heading into the Pacific Northwest will bring
a windy pattern to the western half of the forecast area with
moisture for the mountains. Temperatures will be above normal
through the period and any moisture that reaches the lower
elevations will be light.
Winds already sustained above 25 mph at KLVM and approaching
energy is going to tighten pressure gradients this evening.
Pressure gradients between KLWT and KIDA are expected to double
overnight and local guidance strongly supports wind gusts in
excess of 60 mph later tonight into early Friday along the I90
corridor west of Big Timber including Livingston and also over the
Stillwater River. Current advisory looks good and bigger question
is whether strong winds will impact other areas. Looking at hi res
guidance HRRR ARW and NMM all want to restrict mountain wave
activity to higher elevations overnight and early Friday.
One concern is 70 to 80 kt winds progged at 700mb but pressure
gradients are oriented southerly with this pattern which is
supported by the surface low generating the winds later tonight
moving north northeastward from northwest Montana into Alberta as
opposed to a more easterly track. Will not spread wind highlights
to other areas though would expect very strong mountain winds
overnight.
Heights fall throughout the day on Friday but downslope is a big
factor for the lower elevations. Snow will fall in the mountains
but snow ratios should be fairly low and expect periods of showers
combined with orographics to be the main reason for accumulation
but these will be short bursts. Drier conditions begin to dominate
the plains Friday night into Saturday with lighter winds for a
generally fall day. borsum
.LONG TERM...valid for Sat...Sun...Mon...Tue...Wed...
A progressive flow will prevail over the region during the
extended period, with moist westerly flow and unsettled pattern
moving into the mountains.
Strong ascent moves into the mountains on Sunday and spreads over
the Plains. Dry air will limit shower development from spreading
eastward to the Plains, however likely PoPs over the Beartooths is
expected with transition to snow in the high country during the
evenings.
Pattern remains cool and unsettled with the biggest threat for
precip away from the foothills on Monday as a vigorous front
moves through the area. Gusty wind potential on Sunday/Monday due
to this front as it moves through the Harlowton area.
Seasonable temps with foothills pop chances continue through mid-
week with westerly/northwesterly flow prevailing. Walsh
&&
.AVIATION...
VFR conditions will prevail today and tonight. Wind shear
concerns after sunset at LVM. These stronger winds will begin to
work down to the surface overnight with wind gusts increasing to
45-50 kts late tonight. Walsh
&&
.PRELIMINARY POINT TEMP/POPS...
Tdy Fri Sat Sun Mon Tue Wed
-------------------------------------------------------
BIL 062 049/069 045/064 048/066 046/061 041/056 039/056
0/U 01/B 21/B 12/W 24/W 31/B 22/W
LVM 065 050/062 042/061 045/060 044/055 038/050 036/053
0/N 04/W 32/W 33/W 35/W 32/W 22/W
HDN 062 043/072 045/066 045/068 044/063 040/057 037/057
0/U 01/E 21/B 12/W 13/W 32/W 12/W
MLS 063 042/072 046/067 045/067 045/061 040/057 038/056
0/U 01/E 11/B 11/B 12/W 31/B 12/W
4BQ 067 042/075 046/067 045/072 045/066 040/058 037/058
0/U 00/B 11/B 11/B 12/W 21/B 12/W
BHK 064 040/073 044/064 043/067 042/062 038/054 034/054
0/U 00/B 11/B 11/B 12/W 31/B 11/B
SHR 065 044/073 043/065 041/067 042/063 037/055 034/056
0/U 00/B 11/B 11/B 12/W 22/W 12/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Wind Advisory in effect from 9 PM this evening to 9 PM MDT
Friday FOR ZONES 65-66.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service Houston/Galveston TX
337 PM CDT Thu Oct 13 2016
.DISCUSSION...
The mid and upper level high pressure area that was over South
Texas earlier today has given way to an upper level shortwave
trough moving into the northern and western parts of the state
this afternoon. The front which had moved into the northern and
central parts of the state has slowed down but should work its way
to near the northern counties of the forecast area. An area of
enhanced moisture feeding northward from the Matagorda Bay area
has led to isolated to scattered showers mainly west of the Brazos
River. Other isolated showers have also begun to develop north of
a line from College Station to Conroe to Cleveland.
One issue for tonight will be the possibility of patchy fog. The
SREF probabilities lined up with the area that has experienced
patchy fog issues over the past night or two. Patchy fog will be
most likely over the northern and western counties overnight
tonight past sunrise. The main issue for tonight and Friday will
be the rain chances. The NAM12 has trended toward more widespread
rain chances ahead of the front over the northern third of the
forecast area during the period from late this afternoon to just
after midnight. The HRRR and Texas Tech WRF were a bit later in
the timing - from about mid evening into mid Friday morning over
the same area. Took a blend of the models and lined up the rain
chances and weather with the surrounding offices for tonight and
Friday.
After the 500 mb shortwave trough exits the area late on Friday,
the mid and upper level high pressure area builds back overhead
through the weekend and into early next week. The frontal boundary
will head back northward on Friday and a drier and warmer weekend
will result. Expect temperatures to reach daytime highs around 90
over the inland areas from Sunday through Tuesday. A broad upper
trough will then move across the plains during the latter half of
next week. This trough in turn will help push another cold front
toward the area and raise rain chances on Wednesday and Thursday.
40
&&
.MARINE...
Light to moderate onshore winds will persist into the middle of
next week with seas generally ranging from 2 to 4 feet. A strong
cold front is forecast to move off the coast and through the
coastal waters sometime around Thursday of next week. 11
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 70 89 71 91 72 / 30 20 10 10 0
Houston (IAH) 72 90 73 90 72 / 10 10 10 10 0
Galveston (GLS) 76 85 78 84 78 / 10 10 10 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
Discussion...40
Aviation/Marine...11/47
Area Forecast Discussion
National Weather Service Key West FL
219 PM EDT Thu Oct 13 2016
.DISCUSSION...
A confluent zone has allowed showers with a few thunderstorms to
align in the Straits of Florida early this afternoon. Echoes on KBYX
doppler radar are moving quickly to the southwest thanks to a fresh
to occasionally strong northeast breeze in place. Under partly to
mostly cloudy skies, temperatures in the Keys island chain are in the
middle 80s.
The short range portion of the forecast is based on the most recent
HRRR solution which shows the confluent zone favoring the Straits of
Florida late this afternoon, then shifting further southward through
the evening. The local airmass will continue to destabilize overnight
as the flow deepens from the east/northeast. Expect a chance of
showers and a slight chance of thunderstorms over the next couple of
days. For this forecast cycle, nudged the probability of measurable
precipitation up to 40 percent for Saturday through Sunday thanks to
a shortwave swinging through the region. A pronounced ridge then
pivots eastward towards the southeast coast through early next week
allowing slightly drier air to descend across the local area. A
slight chance of measurable precipitation still looks like a good
advertisement from Monday night onward. Temperatures for the entire
forecast will be very near the seasonal average.
&&
.MARINE...
A small craft advisory will be maintained across all waters
surrounding the Florida Keys tonight, including Florida Bay. Fresh to
occasionally strong northeast breezes are expected over the next
several days thanks to high pressure being reinforced to our north.
Expect a combination of small craft advisories and/or cautionary
headlines for small craft through the coming weekend, and through at
least the first half of next work week.
&&
.AVIATION...
Expect prevailing VFR through the next 24 hours at KMTH and KEYW.
VCSH has been removed from the TAF for the time being as the focus
of shower activity has shifted south of the island chain, but
additional shower activity will be possible this evening. Brisk
northeast flow will continue with gusts near 20 kts until 00z.
&&
.PRELIMINARY POINT TEMPS/POPS...
Key West 77 86 78 86 / 30 30 30 40
Marathon 77 86 78 86 / 30 30 30 40
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...None.
GM...Small Craft Advisory GMZ031>035-042>044-052>055-072>075.
&&
$$
Public/Marine/Fire...04
Aviation/Nowcasts....MCLOVIN
Data Collection......KN
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