Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/25/17
Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
722 PM MST Fri Feb 24 2017
.UPDATE...
Updated forecast for tonight to lower overnight temperatures across
western and northern NM tonight, especially valleys. Winds have
diminished rapidly this evening and likely to decouple completely by
midnight. Given very dry airmass in place, temperatures will plummet.
33
&&
.PREV DISCUSSION...450 PM MST Fri Feb 24 2017...
.AVIATION...
00Z TAF CYCLE
VFR conditions will prevail during the next 24 hours. West winds will
diminish shortly after sunset. West winds will increase at most
terminals Saturday afternoon.
33
&&
.PREV DISCUSSION...255 PM MST Fri Feb 24 2017...
.SYNOPSIS...
Much colder tonight due to a very dry air mass which has overspread
most of New Mexico. A few snow showers may be found over the higher
terrain near the Colorado border and northeast plains tonight. Dry
with highs below average Saturday and some afternoon breezes in the
east, which could lead to critical fire weather conditions over the
northeast and east central plains. A moist westerly flow will bring
increasing chances for rain and snow showers to mainly the northwest
third to half of New Mexico Saturday night through Tuesday but the
east should be relatively dry with some afternoon breezes. High
temperatures will remain below average during this time and may not
recover to near average until late next week.
&&
.DISCUSSION...
Dewpoints have really cratered this afternoon with single digits in
many areas and a few mid to upper teens in the far northeast where
the moisture is relatively more plentiful behind the back door
surface boundary. Potentially a few flurries spread over the nrn mts
and into the northeast, in line with RAP13 and HRRR which have been
fairly persistent with this idea but taper off any minor
precipitation later tonight. Due to the drier air mass, low
temperatures tonight will be colder, especially over the northwest
third by about 5 to 15 degrees and lows overall will be below
average.
Zonal flow Saturday will be dry with some breezes in the east.
Chances for precipitation increase Saturday night and Sunday for
portions of the west and central as a weak trough passes overhead.
Another such feature is expected Monday through Tuesday, but there
looks to be more imported moisture with this second feature,
therefore it may be a more prolific snow producer for some of the
higher terrain and west facing slopes of the northwest, where at
least spotty advisory level snows could accumulate. But neither of
these features would be considered a significant storm system by any
means. Occasionally breezy to windy conditions will impact the east
as well as the higher terrain during this period and overall
temperatures will continue to be below average.
Mid to late next week appears to be dry, although models continue to
have some differences in the formation and location of a closed/cut
off to our southwest. Right now the solutions are mostly dry, and we
may warm to near average late next week.
&&
.FIRE WEATHER...
A progressive pattern through early next week will enhance potential
for critical fire weather conditions on several days. A few notable
features in this pattern will make for challenging decision making.
For today, a back door frontal boundary made it further south and
west than indicated yesterday so it has taken a bit longer for the
humidity to drop to the 10 to 15% range over the east central
plains. The greatest confidence area for critical conditions will be
along and south of I-40 east of Santa Rosa where high temps are
expected to be near normal with moderate haines values. Farther
north and west temps are almost 10F below normal and haines are low.
A red flag warning this afternoon over the east central plains will
expire this evening as winds decouple.
A similar challenge exists for Saturday as winds are shown to veer
around to the southwest over much of eastern NM toward mid day.
Another round of critical fire conditions is possible over the east
central plains and northeast plains Saturday afternoon. Have issued
a Fire Weather Watch for zones 104 and 108. Critical fire conditions
could expand into eastern portions of zones 103 and 107 as well
Saturday. Left it to the overnight shift to decide whether to
upgrade to Red Flag since high temperatures remain below normal and
Haines indices are low to moderate.
Windy conditions will persist into Sunday, however a fast moving
upper level trough will bring increasing mid level moisture and in
turn increase cloud coverage. This will limit fire weather concerns
Sunday. Strong downsloping winds over the east central to northeast
plains continue into Monday possibly producing yet another round of
critical fire weather conditions. Tuesday will see a rinse and
repeat of Sunday with another trough quickly swinging through the
region increasing cloud cover and producing modest precip chances
mainly over the western half of the state.
After Tuesday, the weather pattern quiets down with both the ECM and
GFS showing lower winds and a generally stable environment.
Ventilation rates decrease considerably on Wednesday and Thursday.
Temperatures will rebound to normal to just above normal levels to
by mid to late next week.
24
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch Saturday afternoon for the following zones...
NMZ104-108.
&&
$$
33
Area Forecast Discussion
National Weather Service Caribou ME
1007 PM EST Fri Feb 24 2017
.SYNOPSIS...
A weak back door cold front will move southward into Downeast
portions of the region overnight and then become stationary
early Saturday morning. This front will lift back to the north
across all of the region later Saturday morning and afternoon
as low pressure tracks northwest of the region Saturday evening.
This same low will bring cold front across the area late
Saturday night. Canadian high pressure will then build across
the region on Sunday.
&&
.NEAR TERM /THROUGH SATURDAY/...
1005 pm update...
Temps are dropping acrs nrn Aroostook in wake of bndry that mvd
thru this evng. Snow is falling acrs the St. John Vly with
sleet occurring further south attm. Temps are still abv frzg
south of about a Caribou to Billy-Jack Depot line with a vry
slow drop. 00z raob out of CAR indicated from the surface up to
825mb with latest HRRR about a degree too cold with sfc/925 and
850mb temps. RAP was even colder than HRRR and hv adjusted
things accordingly as models continue to be too cold for the
ovrngt hrs. Thus hv boosted temps up by a degree or so with low
temps being reached arnd 06z bfr stabilizing and then rising twd
daybreak. This has impacted ptypes tonight with just patchy
light frzg rain expected mainly for nrn Aroostook, hwvr colder
vly locations in nrn Somerset and nrn Piscataquis may see a
light glazing and hv kept frzg rain advisory going for current
areas.
Next question bcms dense fog for the ovrngt. Dwpt depressions
are around zero with locally dense fog from about Bangor over
twd the NB border. Coastal zones rmn out of fog with srly flow
allowing some mixing to prevent fog dvlpmnt with areas just to
the north in dead calm winds. Thus, wl issue dense fog advisory
thru 12z. No other chgs needed at this time.
Prev discussion blo...
Rain is finally ovrsprdng the region late this aftn, but temps
both at the sfc and alf up to 850mb are much milder attm then
thought 6 to 12 hrs ago. Also, all models have backed off some
with regard to how much llvl cold air will move Swrd into the FA
behind a weak back door cold front xpctd to settle to Downeast
ptns of the region by very erly Sat morn. This resulted in
making a difficult decision to canx the fzra adv for zones
10...5 and 6, the N Cntrl ptns of the region, orgnly slated for
late tngt into Sat morn. We still believe enough llvl cold air
will likely be present later tngt for lgt fzra for NW and far NE
ME, but not with 100 percent confidence, so this ptn of the
fzra adv remains in effect from 11 pm tngt til 10 am Sat. Any
ice accumulation will be msly a tenth of an inch or less ovr the
fzra adv area.
With most of the first batch of organized ovrrng precip exited N
of the FA by daybreak Sat, msly Chc fzra pops in the adv area
will be left across the adv area Sat morn with sct shwrs and
patchy dz mentioned Swrd to the coast. Fog, which we assigned
with sct shwrs and patchy dz, will become more prominent S to N
across the region late tngt into Sat as both temps and dwpts
rise abv fzg spcly as the front lifts back to the N across the
region later Sat morn into the aftn. Fcst hi temps will not be
achieved until erly eve given the late day surge of llvl warm
air behind the cold front.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
Saturday evening will bring a mild southeasterly breeze ahead of an
approaching cold front. Some scattered showers or patchy drizzle are
possible during the evening ahead of the front. The cold front
will then move across the area around midnight Saturday night
bringing a period of rain. Some of the showers may be heavy and
there`s a potential for an isolated rumble of thunder. Elevated
cape values are up to 300 J/KG as the front pushes through.
Showers will move east and away early Sunday morning as colder
air pushes in. Some snow showers are likely in the higher
elevations to the west early Sunday morning. Colder air will
follow on Sunday as low pressure over eastern Canada moves away
and high pressure builds onto the east coast. Sunday night will
be cold and dry as high pressure moves off the east coast.
Clouds will increase late at night ahead of a weak shortwave
approaching from southern Quebec. Some snow showers will then be
likely across the north late Sunday night into Monday morning
as the shortwave and weak secondary cold front slides across
the north. Temperatures Monday afternoon will then modify into
the mid 30s north and mid 40s Downeast with partial sunshine.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Monday night into early Tuesday should be mainly dry as high
pressure ridges over the region. A weak low with one center racing
across southern New England and another center over the great lakes
will approach Tuesday afternoon possibly bringing some rain or wet
snow Downeast. The main low will approach on Wednesday. Boundary
layer temperatures will likely be cold enough for some snow over the
north. However, a mix changing to rain will be likely Downeast on
Wednesday. The low pushes through and quickly moves away Wednesday
night followed by dry weather in high pressure Thursday into
Thursday night. Another weak low will move in on Friday bringing a
chance for some light snow across the area with the best
chances Downeast as the low tracks south of the Gulf of Maine.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: Northern terminals expected to bounce back and forth
between VFR and MVFR for the first several hours this evening
before eventually settling at MVFR after 03z. BGR and BHB will
likely be IFR/LIFR through the day Saturday in -DZ, FG and low
clouds.
Ptypes will be in question north of PQI with -FZRA expected
after 03z, possibly mixing with PL early. Expect IFR conditions
during the day Sat. Northern zones will likely see LLWS at FL020
toward end of TAF valid time from 19040kt.
SHORT TERM: IFR conditions in low clouds, rain and fog are
likely Saturday night. Conditions should improve to VFR Downeast
early Sunday morning then improve to VFR across the north mid
morning Sunday. VFR conditions across the north Sunday night
will lower to MVFR over the north late Sunday night and remain
VFR Downeast. VFR conditions Downeast and MVFR conditions across
the north are likely on Monday.
&&
.MARINE...
NEAR TERM: No headlines will be needed tngt and Sat...with winds
and seas increasing Sat aftn to near SCA thresholds by erly eve.
Marine fog will likely present spcly late tngt into Sat morn.
SHORT TERM: An SCA will likely be needed Saturday night into
Sunday for gusts up to 30 kt in S winds ahead an approaching
cold front. The SCA will likely have to continue for gusty
westerly winds following the front on Sunday.
&&
.HYDROLOGY...
No changes to the Flood Watch were made with this forecast
cycle. Snow melt from the deep snowpack continues tonight
through Saturday night with rainfall amounts of just over a half
inch by Sunday morning. Water levels are starting to rise
modestly on the river gauges on the Piscataquis and its
branches, but the best response should be later Saturday night
into Sunday. NERFC and ensemble river forecasts continue to
rises into Sunday morning, but nothing that generates strong
concerns at this point. The focus will remain on the southern
half of the forecast area where temperatures will stay above
freezing into Sunday and where more melting has already occurred
with this thaw. Localized ice movement followed by jams is the
scenario to watch...mostly for southern Piscataquis and
Penobscot basins.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...Freezing Rain Advisory until 10 AM EST Saturday for MEZ001>004.
Flood Watch from 7 AM EST Saturday through Sunday evening for
MEZ010-011-015>017-031-032.
MARINE...None.
&&
$$
Near Term...Farrar/VJN
Short Term...Bloomer
Long Term...Bloomer
Aviation...Farrar/VJN/Bloomer
Marine...Farrar/VJN/Bloomer
Hydrology...
Area Forecast Discussion
National Weather Service Cheyenne WY
836 PM MST Fri Feb 24 2017
.UPDATE...
Issued at 836 PM MST Fri Feb 24 2017
The recent snowfall will provide plentiful moisture and with very
cold temperatures tonight, freezing fog will develop across the
North Platte River Valley. Freezing fog has already begun to
develop at Alliance bringing visibility down to 1/2 mile. Based
on the latest hrrr guidance fog for the rest of the North Platte
River Valley beginning around 6Z. All areas will begin to
dissipate by 12Z tomorrow morning.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 243 PM MST Fri Feb 24 2017
Forecast concerns in the short term deal with winds and blowing
snow.
Currently...Still getting some wrap around moisture from the storm
system that moved through the area yesterday and last night.
Light snow echoes being observed on radar mainly east of the
Laramie Range. Aerial coverage is shrinking, so do not think we
will have any more concerns with snow this afternoon. Allowed all
headlines to expire from the winter storm at 11AM today.
Attention turns to tonight as westerly winds return. GFS 700mb
winds increase to 30kts by 06Z and over 40kts by 12Z Saturday
morning. Local high wind guidance showing Craig to Casper
850/700mb height gradients increasing to the mid 40s after 06Z
tonight. WRKGHT guidance slightly higher with close to 50mtrs.
Lots of loose snow out there across the wind prone areas. Thought
it prudent to issue a Blowing Snow Advisory for the wind prone
areas.
One thing the evening and night crew to keep an eye on is strength
of wind. Did go over guidance on winds for the wind prone areas by
10-15 knots. May need to go higher on the overnight forecast. If
we get much higher, we may need to upgrade the advisories to maybe
a ground blizzard warning for the wind prone areas.
Advisories may need to be expanded Saturday after sunrise as
soundings showing 35kts mixing down at Cheyenne, Laramie and
Rawlins.
.LONG TERM...(Saturday night through Friday)
Issued at 243 PM MST Fri Feb 24 2017
Dry but still chilly Sunday with most locations not going above
freezing except for maybe the southern Nebraska Panhandle for
afternoon highs. We start a gradual warmup Monday as the surface
to midlevel flow goes more west to southwesterly ahead of an
approaching shortwave that will cross the area late Monday into
Tuesday. That next shortwave brings our next chance for snow in
across our western areas Monday into Tuesday, with midlevel winds
40 to 50 kts setting the stage for more mountain snow. If stronger
midlevel winds pan out as some model guidance suggests, we could
see a foot of new snow in the Sierra Madre Range with less than
that in the shadowed Snowies. Although not as windy as what we
are expecting for Saturday, the wind prone areas of SE Wyoming
will see wind gusts 40 to 50 mph just about each day with perhaps
Tuesday into Wednesday being a little stronger.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 508 PM MST Fri Feb 24 2017
Occasional MVFR cigs will continue through sunset, then should
trend up to VFR through the remainder of the evening. One concern
for tonight will be fog formation in the Laramie Valley including
KLAR and river valleys across the panhandle tonight including
KCDR, KBFF and KAIA. Latest high resolution guidance shows fog
developing near these locations, with highest confidence at KBFF
and KAIA. Added mention of either VCFG or prevailing IFR fog at
all four locations during the overnight period. Blowing snow
could then be an issue due to winds 20G35kt tomorrow for
KCYS, KLAR and KRWL, but right now it looks like the stronger
winds won`t mix down until after the boundary layer inversion
breaks around 18Z or shortly thereafter.
&&
.FIRE WEATHER...
Issued at 243 PM MST Fri Feb 24 2017
Widespread snow pack will keep fire weather concerns in check
across southeast Wyoming and Nebraska Panhandle through the
weekend. Cold daytime highs will aid in slow snowmelt, so snowpack
could persist into the middle of next week. No fire weather
concerns expected at least through Wednesday next week.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Winter Weather Advisory until 5 PM MST Saturday for WYZ106-110-
116-117.
NE...None.
&&
$$
UPDATE...RJM
SHORT TERM...GCC
LONG TERM...JG
AVIATION...RJM
FIRE WEATHER...GCC
Area Forecast Discussion
National Weather Service Quad Cities IA IL
558 PM CST Fri Feb 24 2017
...AVIATION UPDATE...
.SYNOPSIS...
Issued at 332 PM CST Fri Feb 24 2017
20z surface observations showed a 996mb surface low pressure located
across northern Illinois and Indiana. Cold northerly winds
produced temperatures ranging from the lower 30s over
Independence to lower 40s over Macomb and Princeton. A 500 mb
vort max associated with the trailing upper level low over western
IA and an associated deformation zone helped to spawn widespread
wintry precipiation across much of central Iowa. This vort max was
slowly moving to the east and will serve as the main weather
producer in the short term.
&&
.SHORT TERM...(This Evening through Saturday)
ISSUED AT 332 PM CST Fri Feb 24 2017
Clear slot across the area will pull to the east as the
deformation zone associated with the surface low moves to the east
today and tonight. Main forecast concern will be snowfall amounts
and the diminishing trend of the precipitation.
Actual track and strength of the sfc low was further south and lower
than previously expected. As a result the onset of snow has been
delayed across much of the area until 00z Saturday. Freezing
drizzle has occurred across most of the advisory area. As colder
temperatures and more moisture overtakes the clear slot this
freezing rain will transition into snow.
Guidance has come down in overall QPF amounts from this system.
The HRRR is the less aggressive of all the guidance and suggests
about an inch in overall snowfall for the northern zones. The rest
of the model suite has the northern zones getting 2 to 4 inches.
Our forecast of 1 to 3 inches across northern zones in the winter
weather advisory.
Tomorrow should be free of precip, could see some patchy drifting
snow from the winds, otherwise, main impacts would be slick roads
due to moisture on the roads and the drop of temps into the 20s
and teens.
.LONG TERM...(Saturday Night through Friday)
ISSUED AT 332 PM CST Fri Feb 24 2017
Flow pattern aloft turns zonal to southwest through the first half
of next week ushering in warmer air, with temperatures moderating
back above normal with highs mainly in the 40s/50s. A series of
waves will move through the flow accompanied by precipitation
chances. Very low precip chance for Sunday with onset of WAA and
initial low amplitude wave, but moisture is rather meager. Any
precip should it occur would be sprinkles or light rain, but mostly
virga which could lead to cooler highs than currently forecast
for Sunday. Better signal and subsequent precip chances appear to
be for Tuesday as a stronger wave moves across the Upper Midwest
and Great Lakes. Given this more northerly track consensus from the
models I have kept the precip type mainly rain, with just a mention
of snow Monday night in lead WAA precip potential.
In the wake of the Tuesday system the flow pattern turns northwesterly
for mid to late week. A series of Clipper systems are shown by the
models, one around Thursday and another around Saturday. Both these
systems are shown to pass mainly to our northeast at this time, thus
precip chances appear small as the area will largely reside in dry
warm sector with moisture starved cold frontal passages. Will see
up/down temps during this time favoring above normal in warm sector
ahead of systems then cooling back near to a little below normal in
the wake.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday Evening)
ISSUED AT 550 PM CST Fri Feb 24 2017
An area of light snow will move across the terminals producing IFR/MVFR
conditions with lower conditions with heavier snow at CID/DBQ. After
25/05Z...snow will lessen to flurries or end with MVFR conditions until
around sunrise. Skies will become clear or mostly clear by mid day.
Northwest winds of 15 to 25 MPH will begin to decrease by late afternoon
on Saturday.
&&
.HYDROLOGY...
Issued at 332 PM CST Fri Feb 24 2017
Rainfall in the past 24 hours along with routed flow north of the area
will lead to rises on area streams and rivers. In general though
heavy rainfall was not as widespread, thus the main trend today is for
most crests in next 7 days being lowered by 1/2 to over a foot from
those forecasts issued yesterday and many areas seeing only within
bank rises. This is the case on the Iowa River at Marengo, which is
now staying below FS and therefore cancelled the Flood Watch.
One exception is on the Cedar River, where the recent rainfall combined
with above normal flows has actually led to higher confidence on minor
flooding near Conesville. As a result, I have upgraded the Flood Watch
to a Flood Warning as it is shown to rise above FS within the next
24 hours cresting by early next week. On the Mississippi River, the
recent rainfall along with routed flows will lead to rises over the next
7 days, with several sites shown to reach or exceed flood stage toward
the end of the 7 day period. However, confidence is low given the
noticeable lowering trends past 24 hrs and uncertainties in snowmelt
and amount of routed water north of the area. As a result, no Flood
Watches for the Mississippi at this time, but can`t rule out eventual
watches and possibly a few warnings in the next 7-14 days depending on
snowmelt and routed water.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Winter Weather Advisory until 6 AM CST Saturday for Benton-
Buchanan-Delaware-Dubuque-Jones-Linn.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...Speck
SHORT TERM...Gibbs
LONG TERM...McClure
AVIATION...Nichols
HYDROLOGY...McClure
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
949 PM EST Fri Feb 24 2017
.UPDATE...
Issued at 949 PM EST FRI FEB 24 2017
Current conditions feature the area of showers and storms at the
CWA doorstep along the I-75 corridor. It seems that no dominant
cold pool or organization of the cells in central Kentucky, or
Tennessee for that matter has occurred. Thus, with the cap still
in place over eastern Kentucky, will be hard pressed to see any
severe convection tonight. So have updated to pull the severe
wording from the forecast but have left in the mention of strong
storms with the potential to produce gusty winds and small hail.
Have updated the HWO as well to take out the severe wording and
input the mention of strong storms.
UPDATE Issued at 713 PM EST FRI FEB 24 2017
Current conditions feature a line of showers and segments of
strong to severe thunderstorms in central Kentucky to the west
tracking northeast. Fine tuned the pops to account for a more
timely arrival into eastern Kentucky. Decided to keep the severe
mention in the forecast though, with heating lost and instability
becoming more elevated, the cap in place more and more hints at
any severe weather in eastern Kentucky will be dependent on what
develops in central Kentucky and advects in. Mainly in the form of
a squall line or bowing segments. As well, the main threat
continues to be damaging winds. Onset into Kentucky may be as soon
as 9pm. A new ZFP was sent out to account for these changes.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 517 PM EST FRI FEB 24 2017
South-southwest flow aloft will become more westerly through the
short term as a potent storm system plows through the Great
Lakes, pulling a trough through the Commonwealth over the next 24
hours. Surface low pressure over Lake Michigan will continue to
move off to the northeast, pulling a cold front eastward through
the region, and into eastern Kentucky during the overnight.
A line of thunderstorms currently developing across the Midwest
will move into our forecast area through the overnight period.
HRRR timing of the main line of convection has been fairly
consistent and generally agrees with what has been advertised.
Some thunderstorms could produce severe weather with the main
threat being damaging winds. Hail will be a secondary threat and a
brief, isolated tornado can not be ruled out.
Moisture, or the lack thereof will be the primary limiting factor
to severe weather as dew points will top out in the mid 50s ahead
of the front. Timing of the cold front through eastern Kentucky
will also be a limiting factor. Regardless bulk shear is very
impressive with this system, 40-70 kts, with the majority of the
shear realized in the lowest 3 km. Thus the potential for bowing
cells and line segments will be favored. Surface based
instability to support this storm mode is not ideal but does
appear to be sufficient. Consequently damaging winds are the
primary severe weather threat. This has a distinctive QLCS flavor
to it and considering the environment as a whole feel an isolated
tornado can not be ruled out, though features of this type tend to
be weaker than most and short lived. Low wet bulb temperatures
and freezing levels suggest hail will be a possibility as well.
Colder air invades the coal fields on Saturday and will set
things up for a rather chilly weekend in general. Gusty winds will
combine with strong cold air advection to make for a less than
optimal day for outdoor activities.
.LONG TERM...(Sunday through Friday)
Issued at 315 PM EST FRI FEB 24 2017
The extended portion of the forecast will be fairly active, with
alternating periods of wet and dry weather and warm and cooler
conditions. The period will likely start off dry, with slightly
above normal temperatures Sunday and Sunday night. The pattern is
then expected to shift on Monday, as a weak warm front moves through
the area, bringing persistent southerly flow and warmer air into the
region. Rain showers should begin to move into the area from the
southwest and west late Sunday night into early Monday morning. The
rain will overspread the entire area by late Monday afternoon and
early Monday evening, as an area of low pressure moves along what
will become a nearly stalled out frontal boundary. This pattern is
tentatively expected to persist through late in the day on Tuesday.
A wave of low pressure is then forecast to form along the western
end of the stalled front Tuesday night. This second area of low
pressure is then expected to push eastward on Wednesday, and will
drag another cold front across the lower Ohio valley and Tennessee
valley regions. This boundary may be just strong enough, and just
enough moisture an instability available, for a few thunderstorms to
form along and just ahead of the front, as it moves across the
region. Once the front moves past us Wednesday night, any
thunderstorms should give way to all rain showers. We may even see
enough cold air filter in behind the system to allow some snow to
mix in with whatever rain is left. The last of this precipitation
should be out of the area by late Thursday morning. Thursday and
Thursday night should be mostly dry. There is an outside chance that
a few rain and snow showers will move across the area along and
north of I64 to end the period, with due to uncertainty, this should
be taken with a grain of salt.
Temperatures in the extended on average will be above average each
day, with the warmest days being Monday, Tuesday, and Wednesday,
when the highs will be in the 50s and 60s. Closer to normal values
should be experienced on Thursday, when the mercury is forecast to
max out lower 50s. Nightly lows should be in 30s, 40s, and 50s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
ISSUED AT 713 PM EST FRI FEB 24 2017
Onset of showers and severe thunderstorms will be around 01z
across eastern Kentucky and pushing east through 05z. Have updated
the TAFs to account for this timing. MVFR to IFR visibility due to
the moderate rainfall will be the impacts. a few MVFR cigs will be
possibly but most cigs will remain above 3 KFT. Winds will
continue to be southwesterly gusting to 25 knots at times. Winds
are expected to then increase again tomorrow afternoon with
westerly winds gusting up to 25 knots as well.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SHALLENBERGER
SHORT TERM...RAY
LONG TERM...AR
AVIATION...SHALLENBERGER
Area Forecast Discussion
National Weather Service Memphis TN
723 PM CST Fri Feb 24 2017
.UPDATE...
Updated to expand slight chance for thunder.
&&
.DISCUSSION...
Tasil end of front generating a few storms acros portions of
Central Mississippi. This lightning activity will likely move
into Tallahatchie and Yalobusha counties over the next hour.
expanded threat for storms into this region.
JAB
&&
.PREV DISCUSSION... /issued 620 PM CST Fri Feb 24 2017/
UPDATE..Updated to lower evening PoPs in the east.
DISCUSSION...
Cold front pushing into West Tennessee this hour...with very
isolated shower activity associated with it. As temperatures fall
this evening decreasing instability should keep rain chances
lower than current thinking across the east through midnight. The
threat for a strong storm along the Tennessee River Valley is also
quickly waning...with an update to the HWO likely needed in the
next hour or two. Adjusted the evening forecast accordingly. All
other forecast parameters are currently on track.
JAB
PREV DISCUSSION... /issued 557 PM CST Fri Feb 24 2017/
UPDATE...
Updated for the 00z Aviation Discussion.
PREV DISCUSSION... /issued 338 PM CST Fri Feb 24 2017/
At 3PM...A cold front is currently situated just west and nearly
parallel to the Mississippi River. WSR-88D radar trends continue
to show light rain showers along and north of the forecast area
with just a few along the front. Water vapor imagery shows a
positively tilted shortwave over Iowa at this hour, with severe
thunderstorm watches stacked downstream across much of Indiana
where the best dynamics remain.
For our area, moisture and instability continues to be limited
ahead of the front, as evidenced by high temperatures only in the
60s over much of the area. In addition, the latest AMDAR soundings
from Memphis International Airport also indicate a stout capping
inversion from 850 to 700mb. The latest HRRR run indicates that
best chances for rain and thunderstorms will be across west
Tennessee and northeast Mississippi through about 10 PM tonight. A
few storms could be strong near Henry and Benton County, Tennessee
where the best forcing for ascent will be. Elsewhere, showers and
some elevated thunder will be possible as the front pushes quickly
across the area tonight.
Cool Canadian high pressure will build into the region on
Saturday with temperatures remaining only in the upper 40s and
lower 50s during the day. The surface high will become nearly
centered over the Mid-South by Sunday morning, resulting in
optimum radiational cooling. Guidance continues to trend cooler
with low temperatures, and most places will drop below the
freezing mark for the first time in over a week. A warming trend
will begin again on Sunday as high pressure slides eastward, and
winds turn around to the south.
Both main synoptic models continue to show a shortwave kicking
off a few showers after midnight Sunday and overspreading the
entire area by Monday morning. A broad surface low is expected to
develop over the Central Plains and push a warm front northward
through our area during the day on Monday. As it lifts, showers
and thunderstorms will be possible much of the day. The
aforementioned surface low will traverse to the great lakes during
the day on Tuesday and drag a cold front into our area by late
Tuesday night. The models continue to diverge past this point,
with the GFS pushing the front all the way through our area by
Wednesday morning keeping us dry for the day, whereas, the Euro
keeps it nearly stationary as a weak surface low rides along the
front. Thus, the Euro keeps us in a wet and unstable airmass all
day on Wednesday, contrary to the dry GFS solution. The GFS
continues to be the outlier, with respect to evolution of the
upper level flow.
Thursday into next weekend continues to be dry at this point, as
zonal flow and slight upper level ridging remain in place over the
Mid-South. Temperatures look to return to seasonal readings with
highs near 60 and lows in the 40s.
AC3
&&
.AVIATION...00z TAFs
VFR conditions will prevail through the period. A few showers and
maybe a thunderstorm near KTUP this evening can be expected as a
cold front moves through the region. Gusty southwest winds will
veer northwesterly behind the front with continued gusts. This
should persist through midday Saturday before gradually
diminishing. Skies will clear at all sites later this evening.
JLH
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
Area Forecast Discussion
National Weather Service Nashville TN
900 PM CST Fri Feb 24 2017
.UPDATE...
FOR EVENING DISCUSSION.
&&
.DISCUSSION...
Forecast is really on track this evening. We`ve been monitoring
convective activity on what seems to be a pre-frontal trough over
the last couple of hours. A couple of cores have peaked out at
decent heights, but with dew points in the low to mid 50s ahead
of this trough, we`re not getting the surface based instability to
really help spike these storms at anything more than "strong".
Pea and dime-sized hail is the largest report we`ve had since the
beginning of the convection. That`s not to say one or two
couldn`t become severe over the next few hours, but our potential
for anything widespread is really looking low right now. Biggest
threats through the remainder of the evening will continue to be
damaging gusty winds and large hail as the 00Z sounding from OHX
showed 500 mb temperatures around -18 degrees C and relatively
steep mid-level lapse rates.
The interesting element in all of this is the lack of consistency
between some of our models regarding any development on the front
itself over the next several hours. The HRRR has had the majority
of the development on this pre-frontal trough, where the NAM
shows the development on the front itself, which is currently back
over W Tennessee, nearing Clarksville. With the limited
instability, I still think the best money is on this pre-frontal
trough for any severe potential this evening.
&&
.AVIATION...
00Z TAF DISCUSSION.
Chances for showers and thunderstorms will move in this evening
from west to east, and look to impact all terminals. Looking at
short term model consensus, KCKV looks to see showers and VCSH
from around 00Z through 05Z, KBNA from 02Z through 06Z, and KCSV
from 03Z through 07Z. Current thinking is thunderstorms will
mainly impact KBNA and KCSV, and will bring chances for MVFR/IFR
vis and MVFR cigs during thunderstorm passage for KBNA around
02Z-05Z and for KCSV from 05Z-08Z. After the cold front passes,
winds will flip to the northwest and remain around 10 to 15 knots
sustained with gusts to around 20 knots. Some models are placing
MVFR cigs again during the morning hours after sunrise, but left
out mention for now in the TAF until short term models remain
consistent with the MVFR cig solution.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION......Unger
AVIATION........Barnwell
Area Forecast Discussion
National Weather Service Charleston WV
1018 PM EST Fri Feb 24 2017
.SYNOPSIS...
A strong cold front crosses pre- and post- dawn Saturday
morning, followed by cooler weather for the weekend. A couple
systems next week with precipitation chances.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 1010 PM Friday...
Prefrontal line of strong storms poised to cross into our
southeast Ohio counties in the next 1 to 2 hours. Much of the
activity over the last few hours has been strong to only
marginally severe. The prospects for severe wx thankfully appear
to be waning overnight with southeast Ohio standing the best
chance for some damaging wind gusts in bowing segments within
the line.
As of 645 PM Friday...
See latest PNS/RER for info today`s records, February all time
records, and all time record meteorological winter highs.
Forecast generally in good shape. I tweaked hourly pops using
latest HRRR as an aid. There is still a concern for locally
damaging wind gusts after midnight across southeast Ohio,
northeast Kentucky and western West Virginia. The mid level
capping currently in place will erode overnight with the
approach of the front. With steepening low level lapse rates
along with the low dewpoint spreads in place...concern exist for
a congealing QLCS bringing down strong downdrafts.
As of 315 PM Friday...
After a record breaking warm afternoon and a dry, mild evening,
a strong cold front still appears on track to bring a line of
showers and thunderstorms through the area just ahead of it
overnight into Saturday morning. The main convective threat is
wind damage as super cells that form upstream evolve into a fast
moving squall line, but the hail and even tornado threat could
not be entirely ruled out if the low level shear can give rise
to sufficient mesoscale organization.
Dry slot behind the cold front will bring a quick end to the
showers and thunderstorms from west to east on Saturday, but
wrap around precipitation will then spread into northern
portions of the area later Saturday afternoon. These rain
showers will start turning over to snow showers late, as much
colder air advects in.
Used a blend of primarily near term sources for hourly
temperatures in the warm air ahead of the front tonight, and in
the cold advection behind the front on Saturday. Lows tonight
will be close to or equal to highs Saturday.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/...
As of 330 PM Friday...
Cold air advection on W/NW flow will bring the chance for
upslope snow showers across the mountains through early Sunday
morning. Moisture is limited so accumulations will be very light
with generally less than an inch. High pressure builds over the
area on Sunday and although we remain dry it will be cool
relatively speaking. High pressure should hold through most of
the day Monday, however a southern stream system will approach
Monday evening and showers enter SW West Virginia by 00Z
Tuesday out ahead of a warm front.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
As of 335 PM Friday...
Zonal flow aloft will make for a progressive and active
pattern next week. Our first system brings showers Monday night
into Tuesday. The next system will arrive mid week as low
pressure tracking across the Great Lakes drag a cold front
through the region. Behind this colder air arrives again on NW
flow and this will bring a chance for snow showers across the
mountains towards the end of the work week.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
As of 645 PM Friday...
A strong cold front will impact the area overnight tonight into
early Saturday morning. A line of strong showers and
thunderstorms just ahead of the cold front is timed to reach HTS
near 08Z, PKB 09Z, CRW 10Z, CKB,EKN, and BKW around 11Z.
Inserted tempo groups for HTS/PKB where 9 hour policy allows for
IFR TSRA with wind gusts to 40 kts. I covered the remainder of
the sites with 1 to 2 hour prevailing conditions of IFR gusty
showers. Some of the winds may approach severe limits across
HTS/PKB/CRW.
Conditions will improve to VFR across the lowlands Saturday, as
dry air and a rising frontal inversion increases mixing heights
to about 5-6 kft.
South to southwest surface flow will be gusty at times ahead of
the cold front, shifting to west and remaining gusty behind the
cold front early Saturday morning. Moderate south to southwest
flow aloft ahead of the cold front into tonight will become
moderate west behind the cold front on Saturday.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SUNDAY...
FORECAST CONFIDENCE: Medium to high.
ALTERNATE SCENARIOS: May need to add TSRA to prevailing for
remainder taf sites. Gusty winds will tend to vary, especially
with the convection and the passage of the cold front overnight
tonight into Saturday morning.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE SAT 02/25/17
UTC 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14
EST 1HRLY 22 23 00 01 02 03 04 05 06 07 08 09
CRW CONSISTENCY H H H H H H H M M H H L
HTS CONSISTENCY H H H M H M M H H H H M
BKW CONSISTENCY H H H H H H H H M L L L
EKN CONSISTENCY H H H H H H H H H H M L
PKB CONSISTENCY H H H H H H L H H H H M
CKB CONSISTENCY H H H H H H H H H H H M
AFTER 00Z SUNDAY...
No widespread IFR conditions are expected at this time.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...None.
OH...None.
KY...None.
VA...None.
&&
$$
SYNOPSIS...TRM/MPK
NEAR TERM...TRM/30
SHORT TERM...MPK
LONG TERM...MPK
AVIATION...30