Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/16/18
Area Forecast Discussion
National Weather Service State College PA
1047 PM EST Thu Feb 15 2018
.SYNOPSIS...
A complex frontal system will move through the region overnight
and early Friday. Cooler and drier weather will move in for
Friday before a new frontal system brings more inclement
weather for late Saturday through early Sunday.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
The nose of the low level jet is surging through SRN PA
resulting in a shot of strong warm advection and potent moisture
convergence. RAP shows the LLJ continuing eastward and settling
south along or just south of the MD border after midnight.
Locally heavy rain is falling from Somerset east into the Lower
Susq Valley. We got a call earlier of some minor road flooding
in Somerset and with the convective-type moderate to heavy rain,
we have issued a couple of advisories for minor flooding.
The deep and extensive moisture plume that extends all the way
from the tropical Pacific south of Baja Mexico will yield a
high precipitation efficiency into the overnight. Add in an
upslope/orographic component, and we`ll see some heavy storm
total rainfall (2+ inches) tonight and early Friday over Cambria
and Somerset counties, which remain in a flood watch. Am a
little concerned about the potential for flooding over Bedford
and Blair where the HRRR wants to bring some local storm totals
of around 2 inches, but for the most part the meso models are
consistent with confining the biggest rain totals to the higher
elevations. The latest HRRR shows a stripe of 1 to 1.5"
rainfallsfrom northern Cambria all the way to the Harrisburg
area and into northern Lancaster county. Details are in the
Hydro section below.
Min temps tonight will be very mild and in the 50s in the SE,
but in the lower 30s in the far NW where an early morning
cold FROPA will send temps tumbling just before sunrise.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
A strong cold front pushes SE through the region Friday morning.
The mild weather will be erased (albeit just for a rather brief
48 hour period) as a cold front sends temperatures falling
slowly but steadily through the daylight hours on Friday.
The dry air will also kill off the rain before noon in many
places - except the Laurels. There will likely be a transition
zone from rain to snow across the northwest 1/2 of the area with
a slushy accumulation possible over the higher terrain as the
colder air catches up with the back edge of the frontal precip.
But, the drying occurs so quickly and temps mild enough over the
south that no snow is expected SE of UNV/AOO/IPT. Clearing and
good CAA will bring sfc temps down into the lower teens in the
NW, and uTeens and l20s elsewhere.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
Period starts off with high pressure moving quickly west to east
across the state. Weak and fast moving low pressure center is
forecast to develop over eastern NC Saturday afternoon, an move
to off the NJ coast overnight into Sunday morning. This could
bring a swath of 2-4 inches of snow to much of central counties
with a little less to the north and a little more to the south
and east. Of some concern is the air and ground temps at the
start of pcpn...this may limit accumulations til sfc temps can
cool off.
System clears out quickly for Sunday with a mild pattern
resuming next week with rounds of rain targeting the northwest
1/2 of the area. Temps will be back into the 50s and 60 or so by
Tues and remain mild into mid- week.
&&
.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
TAFS updated.
Visibilities remain rather good...even with the rain.
Earlier discussion below.
00Z TAFS sent.
00Z TAFS close to earlier package. Main thing was to add more
detail later on Friday.
A moist southwest flow ascending the Allegheny Mountains will
result in persistent MVFR cigs at KBFD/KJST through dusk, This
will be followed by quickly lowering cigs spreading across the
region this evening, as an area of low pressure approaches from
the midwest and tracks across Pennsylvania tonight, resulting in
rain of varying intensity and deteriorating cigs/vsbys.
Cold front moving faster now...than what models had several
days ago.
Expect clearing from northwest to southeast later on Friday.
Some snow may occur on the back side of the cold front across
the northwest.
Outlook...
Sat and Sat night...Snow spreading northeast across the state
late Sat and continuing into early Sunday with widespread IFR
and LIFR restrictions.
Sun...Clearing.
Mon and Tuesday...Periods of Rain/low cigs possible, especially
NW Mtns.
&&
.HYDROLOGY...
PWATs climb to 30mm - nearly 5 standard deviations above
normal. Upslope and prolonged time of rain will result in 2-3
inches of rain in the Laurels and 1-2 inches across the middle
third of the area. The greatest threat for flooding exists in
the Laurels, but some minor problems may crop up in the central
mtns. At this point, not enough to worry about in the central
mtns for a flood watch. Much of the snow is melting, but the
pack is dense, now. 50 dewpoints and strong SW wind will help
melt quite a significant amount away today and tonight in the W.
Streamflows are already well above normal (>75th percentile) in
the southern half of PA right now. So, the rain will be
excessive, and flooding is almost likely in the Laurels. The WPC
outlook of a SLGT risk of excessive rainfall matches up nicely
with the area covered by the watch.
&&
.EQUIPMENT...
The radar is down with a malfunctioning motor. Techs are in the
process of trying to install a replacement.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Friday evening for PAZ024-033.
&&
$$
SYNOPSIS...La Corte
NEAR TERM...La Corte
SHORT TERM...Dangelo/Lambert
LONG TERM...Dangelo/Gartner
AVIATION...Martin
HYDROLOGY...La Corte
EQUIPMENT...La Corte
Area Forecast Discussion
National Weather Service Goodland KS
741 PM MST Thu Feb 15 2018
.UPDATE...
Issued at 737 PM MST Thu Feb 15 2018
Despite decent returns shown on the radar, observations have not
been showing snow making it to the ground. Upstream 00z soundings
do show a very moist air mass. Forcing is strong but lower levels
are becoming more stable as well. Latest Hrrr and Rap keep the
main precipitation in eastern Colorado and current analysis
supports that. So will keep the highest pops and what little snow
there is out in eastern Colorado. Otherwise just made minor
adjustments in the remaining hourly grids.
&&
.SHORT TERM...(This evening through Friday)
Issued at 218 PM MST Thu Feb 15 2018
Across the Tri State region this afternoon...skies are a partly to
mostly sunny mix with temps mostly in the 50s w/ some 40s north as
frontal boundary starts to push south into the region. Winds are
northerly and gusting to 20-30 mph.
Going into tonight...with front continuing push thru the region...do
expect northerly winds to persist at least thru 06z-07z before
tapering off as high pressure builds south into the Plains region.
With an upper level shortwave moving across the region tonight and
upslope effects ahead of the ridge...some light precipitation is
expected. Little to no QPF with this...but enough to transition
light rain over to a light snow as temps fall this evening.
Continued with model/forecast trend with bulk of snow(less than
0.5") over NE CO and bordering locales. With winds gusting to the 30-
40 mph range...some patchy blowing snow is possible. Overnight lows
in the mid and upper teens.
For Friday...precip will end by sunrise putting area in colder
airmass even with a shift to SSW flow thru the day. Will be looking
for just below normal highs in the upper 30s to mid 40s under sunny
skies.
.LONG TERM...(Friday night through Thursday)
Issued at 100 PM MST Thu Feb 15 2018
Friday night-Sunday: Shortwave ridging transitions over our CWA
Friday night, with west then southwest flow developing Saturday
through Sunday. Pattern will remain dry with a warming trend through
the weekend. A quasi-stationary front lingering through Saturday
morning eventually lifting north as a warm front as lee trough
deepens Saturday afternoon. Strongest WAA Sunday may be associated
with strong southwest flow ahead of an approaching arctic front.
Surface pattern and mixed layer winds are uncertain Sunday which
will determine potential for RFW conditions to be met. Due to the
mild temperatures and dry air mass in place RH will likely reach 15
percent at least for a period in the afternoon Sunday.
Sunday night-Thursday: Longwave trough develops across the western US,
with an arctic front moving over our CWA Sunday night and Monday.
Several shortwave troughs break off the main upper low and
transition across the Rockies and Plains, and could result in
increasing snow chances (deepening on evolution/track). Models are
coming into better agreement for snowfall Monday night through
Tuesday morning, however still vary on amounts. ECMWF shows a
stronger lobe of vorticity and more of a closed H7 center which
would represent better potential for stronger forcing in our NW CWA.
GFS is weaker and shows less amounts accordingly. For now consensus
is for sub advisory amounts (generally around 1"), but this could
change if we see good banding and a slower transition eastward.
Shortwave ridging is currently shown to move over our CWA by
Thursday and help bring dry conditions and a slow moderation in
temps (particularly Thu ahead of next trough).
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 439 PM MST Thu Feb 15 2018
A strong cold front is currently moving through the area. For
Kgld, north winds of 15 knots with gusts to 23 knots will increase
to 21 knots with gusts to near 29 knots. By 02z mvfr conditions
with move into the site along with light snow, 6sm or greater
visibility. At 06z the winds will decrease to near 14 knots with
vfr conditions returning and what snow there was to the south of
the site. In the 10z to 12z time frame the winds will become light
and variable. Late in the morning those winds will shift to the
south and increase to near 13 knots. Around 20z those winds will
increase to near 17 knots with gusts to near 23 knots.
For Kmck, north winds near 12 knots will increase to near 20 knots
by 02z with gusts into the 25 to 30 knot range. Also near 02z
conditions will become mvfr and continue until 06z. At 06z vfr
conditions return for the rest of the period with the north winds
decreased to near 12 knots. Near 11z those winds will become
light and variable. Around 18z the winds will shift to the south
near 11 knots and will continue until the end of the period.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...JN
LONG TERM...DR
AVIATION...BULLER
Area Forecast Discussion...UPDATED
National Weather Service Huntsville AL
750 PM CST Thu Feb 15 2018
.NEAR TERM...(Tonight)
Issued at 750 PM CST Thu Feb 15 2018
The 00Z RAOB indicates a strongly capped airmass this evening. This
should prevent shower development late tonight for most areas, mainly
south of the TN River. The latest HRRR continues to suggest isolated
showers will be possible further north, and will leave that in the
forecast. A mild night is ahead, and temperatures have only dipped
into the middle 60s to around 70. The middle 60s in a few spots will
necessitate a lowering of minimum forecast temperatures by a small
amount, but otherwise, the rest of the forecast looks in pretty good
shape. South winds will stay at 5-10kt, at times reaching near 15kt,
mainly in southern TN and far northwest AL.
.SHORT TERM...(Friday through Saturday night)
Issued at 308 PM CST Thu Feb 15 2018
Models suggest that a mid-level trough to our northwest will
continue to dampen and shift east-southeastward across the lower
Great Lakes and into the central Appalachians by 00Z Saturday. As a
result, the associated cold front will very slowly push southward
through the region tomorrow--likely entering the northwest counties
by 15-16Z, and exiting the southeastern counties around 20-21Z. A few
morning showers will be possible in the WAA regime south of the
front, with a band of more scattered shower activity along the front
expected to gradually diminish as it pushes southward through our
region. To the north of the front, an area of light-moderate
stratiform rainfall will primarily impact portions of KY/TN, but may
shift as far southward as the northern half of the HUN forecast area,
and only for this reason have we left likely POPs in the forecast
tomorrow.
The cold front is predicted to stall across central AL Friday
evening, with moderate northerly winds subsiding and veering to the
northeast as a ridge of high pressure shifts eastward from the mid-MS
Valley into New England. It still appears as if winds above the
shallow frontal inversion will back to the southwest and increase
considerably between 09-12Z Saturday, in response to another
amplifying 500-mb trough digging southeastward across the northern
Rockies. Based on indications of favorable isentropic ascent and
abundant moisture in the layer where lift will be maximized, the
result should be regeneration of light rainfall, which will spread
east-northeastward into the region before dawn.
Guidance now indicates that a weak surface low related to the
northern stream mid-level trough will develop along the northwest
Gulf coast by Saturday morning and track east-northeastward across
central AL and into the Carolinas by sunset. A broad area of
moderate-locally heavy rainfall will accompany the low, with the most
widespread coverage of rain expected to occur to its immediate
northwest. Given some uncertainty on the track of this system, we
have indicated slightly higher POPs for the northwest half of the
area on Saturday, and this will preclude issuance of a region-wide
Flood Watch at this point. However, based on forecasted rainfall
totals ranging from 0.5-1 inch (along with locally higher amounts),
we could certainly see an uptick in mainstem river and tributary
flooding with this event. Although stratus clouds will persist for
much of the night, rainfall should be shifting eastward early
Saturday evening, with lows falling into the u30s-l40s.
.LONG TERM...(Sunday through Wednesday)
Issued at 308 PM CST Thu Feb 15 2018
The subtropical ridge will build northeastward and into the TN
Valley through the first part of the long term period, with winds
aloft becoming southwesterly. This will combine with southerly
surface flow to allow an abundance of moisture to surge northward
across the area. Temperatures on Sunday will be somewhat mild, with
highs expected to warm into the lower 60s. Isolated showers, and
possibly a thunderstorm, will also be possible during the day,
generated mainly by weak isentropic lift. A weak area of vorticity
will intensify somewhat as it moves eastward and into the region late
Sunday night, which may generate a greater coverage of showers,
though still only scattered in nature. Meanwhile, southerly flow and
cloud cover will keep overnight lows from falling too much with temps
only falling into the upper 50s.
The southwesterly flow in the mid and upper levels will increase
through the day on Monday as an upper trough ejects just west of the
Rockies. This will place the TN Valley under a pattern more
reminiscent of late spring. Isolated to scattered showers will be
possible through the day across the TN Valley given that abundance of
moisture and continued isentropic lift. These showers may end up
being more diurnally driven, meaning the potential for thunderstorms.
But given some uncertainty in mesoscale details that can`t be
resolved this far out, will keep only scattered showers for now.
Temperatures will be rather warm, with highs on Monday climbing into
the lower 70s. Isolated showers may continue into the evening hours
Monday night, though dry conditions are expected by midnight.
Overnight lows will be more like what we see in the late springtime,
with temps only falling into the lower 60s.
The upper trough will continue to push eastward and move into the
Plains during the day Tuesday, with the associated cold front moving
into the Ohio and Mississippi Valleys. Models are in much better
agreement today than yesterday, but discrepancies still remain with
the ECMWF only a few hours slower than the GFS. Tuesday may be dry
for the most part, though southerly flow will continue the influx of
moisture ahead of the cold front. At this point it looks like the
front will move into the area overnight Tuesday and then slowly move
eastward through the early morning hours on Wednesday. Isolated
thunderstorms will be possible just along the front, given at least
elevated instability in place. It`s a little early to start talking
about any threats associated with this front, given the timing
uncertainties, but the nocturnal movement, along with a general
weakening of the upper level support, will mean a less favorable
environment for severe thunderstorms. The front will generally stall
just south of the region Wednesday, keeping the chance for showers
through the day. Temperatures on Tuesday will be borderline hot, with
highs reaching into the upper 70s. Overnight lows will only fall
into the 60s, and with the current timing of the front (early
Wednesday morning), we`ll see our highs in the morning with temps
falling through the day.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 419 PM CST Thu Feb 15 2018
VFR conditions should last thorugh this evening and into the
overnight hours, with scattered to broken layers at 030-050agl. Lower
stratus ~015-025agl (MVFR) should develop by 10Z at both KMSL and
KHSV with isolated to scattered showers possible. A cold front will
arrive ~16Z at KMSL and ~17Z at KHSV bringing light rain and
additional low clouds. Winds will also shift from southwest to
northwest, and then gust around 20kt through the rest of the period.
&&
.HUN WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
TN...NONE.
&&
$$
NEAR TERM...17
SHORT TERM...70/DD
LONG TERM...73
AVIATION...17
For more information please visit our website
at weather.gov/huntsville.
Area Forecast Discussion
National Weather Service Wilmington OH
943 PM EST Thu Feb 15 2018
.SYNOPSIS...
Widespread showers will push across the area tonight into Friday
as a slow moving cold front interacts with a very moist airmass.
High pressure and drier, colder air will arrive for Friday night.
More precipitation is expected Saturday when low pressure is
forecast to travel across the Southern Appalachians.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Ahead of a cold front that is currently just outside the ILN CWA
to the northwest, continuous southwesterly flow is continuing to
moisten the atmosphere, with widespread rain (and embedded heavy
showers / a few thunderstorms) now impacting the forecast area.
The 00Z KILN sounding showed an atmosphere with little in the
way of instability, but just enough to allow for some convective
development within the regime of LLJ convergence. A broken line
of convection in southern Indiana will eventually impact much of
the southern half of the ILN forecast area. Individual storm
motions are generally west-to-east while the line is more
oriented WSW-to-ENE, but some elements within the wavy line of
convection (including some moving through the west-central
sections of the forecast area right now) are more parallel to
the flow. This will allow a continued threat of prolonged
moderate to occasionally heavy rainfall, and some additional
flood advisories will likely be needed as the night progresses.
Still a chance of some flood warnings depending on the
orientation of the convection. Winds have yet to become an
issue, with a noted loss of momentum in the lowest 1kft of the
atmosphere (as per TIDS/TDAY radar data) keeping the stronger
flow from reaching the surface.
Previous discussion >
Atmospheric river extending from the Eastern Pacific to the
Ohio Valley evident on Channel 10 of GOES-16 is the source of
moisture leading to our weather problems. Heavy rain is expected
due to near record PWATs being lifted along the slow moving
cold front that is nearly parallel to the potent mid level
flow. Widespread rain showers that have developed out ahead of
the cold front are impacting northern portions initially, before
moving south across the area this evening through tonight as
the front sags southeast, pushed by the strengthening mid level
jet. Efficient rain processes will lead to one to locally two
inches of rain falling on saturated ground, causing localized
flood problems. Therefore, Flood Watch remains in effect through
Friday afternoon.
Kept chance of thunderstorms through this evening for
convection forming in an atmosphere containing up to 500 J/KG
CAPE. Supported by strong veering wind fields, marginal risk for
severe thunderstorms is being limited by the rather low
instability.
Very warm temps in the 60s this evening will fall off overnight
as the cold front moves in, with readings by 6 am ranging from
the mid 30s over West Central Ohio, to the 40s in metro areas,
up to around 50 far southeast.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
Cold front containing near record PWATs will be near the
southern border of the FA Friday morning. Most heavy showers
will have ended, but lighter showers should linger into the
afternoon especially in southern locations. Flood watch
continues until 2 pm for localized high water problems, while
runoff not mitigated by vegetation arrives in streams that will
undergo rapid rises.
The showers behind the cold front should be out of the FA by
Friday evening, and 1029 mb high pressure traveling through
Northern Ohio is forecast to bring dry weather Friday night.
Temperatures will show a non-diurnal decreasing trend Friday in
strong cold advection on a northwest low level flow. This will
yield readings in the mid and upper 30s most locations by
Friday afternoon, a 30 degree drop in 24 hours. Lows in the 20s
are forecast for Friday night.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
Approaching s/wv energy in the quasi-zonal flow aloft will perturb a
weak wave of low pressure to our southeast along old frontal
boundary on Saturday. The s/wv will combine with upper level
divergence from the RR quad of an upper level jet, allowing
precipitation to spread northeast through the day. A weak boundary
to our west may also aid in some precipitation development. In all,
highest PoPs are still slated for our southern/eastern zones, with
lower PoPs northwest. It will be cool on Saturday, 30s to lower 40s.
Some of the precipitation may be a rain/snow mix, especially north.
This mix will be highly dependent on the rate of precipitation and
the degree of the web bulb effect/evaporative cooling to lower the
freezing levels. Some minor accumulations of a tenth or two could
accumulate on grassy surfaces late in the day and into the evening.
For Saturday night, energy will quickly push east, allowing the
precipitation to come to an end by midnight. Skies will become
partly cloudy with lows in the upper 20s to the lower 30s.
Sunday will be the least active weather day in the extended as high
pressure traverses the Ohio Valley. Under sunshine, highs will
moderate into the 40s to lower 50s.
Models continue to advertise an active weather pattern for next
week. Thus, the threat for additional flooding will continue. The
upper level flow pattern becomes amplified as a strong subtropical
ridge builds off the southeast U.S. coast while large scale mid
level troughing develops across western Canada/western U.S. This
setup will transport rounds of moisture northeast across the Great
Lakes and Ohio Valley. The first round is expected Sunday night into
Monday as a low level/moist jet in association with a warm front
pushes northeast across the area. In the warm sector, highs will
warm into the 60s most locations on Monday. For Monday night into
Wednesday night, a very slow moving frontal boundary will be the
focus for more rounds of precipitation. It will be unseasonably warm
on Tuesday with some cooler air slowly moving back in by Wednesday.
By weeks end, there could be a respite in the probability for
precipitation by Thursday as front tries to move east/southeast of
the region. However, activity may ramp up again by Friday and into
next weekend as s/wv energy begins to affect the Great Lakes and
Ohio Valley once again.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Though a brief period of VFR conditions is occurring as of 23Z,
rain (and possibly thunderstorms) will be moving into the TAF
sites over the next several hours. This will lead to MVFR
conditions, and possibly temporary IFR conditions, especially
at KCVG/KLUK/KILN. MVFR to possibly IFR conditions will continue
into the overnight hours, but eventually rain will come to an
end by morning, with MVFR ceilings persisting well into the day.
Winds tonight will remain out of the southwest with gusts of
20-25 knots, but there will be a wind shift overnight to the
northwest, and some gusts may continue. Northwest winds of 10-15
knots (gusts to around 20 knots) will continue on Friday.
OUTLOOK...MVFR conditions are expected to continue through
Friday before clouds scatter out. MVFR conditions are possible
again on Monday into Tuesday.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...Flood Watch through Friday afternoon for OHZ043>046-051>056-
061>065-071>074-079>082-088.
KY...Flood Watch through Friday afternoon for KYZ100.
IN...None.
&&
$$
SYNOPSIS...Coniglio
NEAR TERM...Coniglio/Hatzos
SHORT TERM...Coniglio
LONG TERM...Hickman
AVIATION...Hatzos
Area Forecast Discussion
National Weather Service Lincoln IL
905 PM CST Thu Feb 15 2018
.UPDATE...
Issued at 905 PM CST Thu Feb 15 2018
Cold front has almost moved through the CWA and is still going
through parts of southeast IL, where rain continues to fall.
Mostly cloudy skies will also continue across the CWA overnight
behind the front with northwest winds of speeds around 10 mph.
Winds actually decrease some along the front, but increase behind
it. Current forecast looks ok, but will make some adjustments in
the grids for less fog and clean up the pop/wx grids. Update will
be out soon.
&&
.SHORT TERM...(This evening through Friday)
ISSUED AT 232 PM CST Thu Feb 15 2018
Looks like the warm front made it about as far north as a Macomb
to Peoria to Chenoa line today, with the fog still lingering to
the north early this afternoon. High-res models suggesting this
fog may hang on for a few more hours. Current advisory expires
at 4 pm, and will make a last minute decision on whether it needs
to be extended or not.
Surface low is currently centered near Quincy, and will ride
northeast along the boundary the rest of the afternoon as the
associated cold front pushes southeast. Short-range models have
this latter boundary near I-70 around sunset, but only slowly
moving across the southeast CWA this evening. Temperatures south
of the front have reached the 60s, with a few lower 70s south of
I-70, where wind gusts have been in the 30-40 mph range. This has
contributed to some surface based CAPE`s around 200-300 J/kg down
there, which the RAP suggests could come up a bit more this
afternoon. SPC Day1 outlook around midday added a marginal risk
of severe weather near and south of I-70. Will keep a mention of
isolated thunder into early evening. High-res models show more of
a widespread shower issue there much of the evening, before the
front finally pushes south.
Much colder conditions still on tap for Friday, as an upper level
wave passes to our north. No significant push of Arctic air is
expected, so temperatures in much of the CWA should still reach
into the 30s outside of any lingering snow cover.
.LONG TERM...(Friday night through Thursday)
ISSUED AT 232 PM CST Thu Feb 15 2018
Upper level pattern gradually will feature a southwest flow into
our area by early next week. Temperatures should get back into the
50s by Sunday and 60s Monday. GFS and ECMWF show more of a split
flow by mid week, which should keep the coldest air further
north.
Main issue in the longer term will be with an extended period of
rain chances, which could result in some hefty totals over parts
of the CWA. This is mainly beginning early next week, when a
storm system develops over the central Plains early Monday. Our
forecast area will remain in the warm and more humid sector
through the first part of Tuesday, before an upper wave over the
northern Plains gives the cold front an eastward shove.
Precipitable water values off the GFS are around 1.3-1.4 inches
Monday night and early Tuesday, which is near record territory for
this area for the latter part of February. WPC guidance and model
blends suggest a few inches of rain possible over the southeast
CWA through mid week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 554 PM CST Thu Feb 15 2018
VFR conditions will prevail at SPI/DEC/CMI overnight and into
tomorrow. However, there is the possibility of MVFR cigs during
the daytime hours tomorrow, ending around noon, then VFR returns
for afternoon. This will not be the case for PIA and BMI where
dense fog is still possible this evening. As front continues to
move southeast this evening a few showers are still possible at
SPI/DEC/CMI but this should end at all three sites around 02z.
Then expecting AC over the area as the SC clouds decrease. An area
of lower/MVFR clouds will arrive overnight in the north and then
progress to the south, reaching SPI/DEC/CMI around 11z. This will
last til early afternoon. All sites will see VFR conditions
tomorrow afternoon. Winds will be northwest behind the front at
PIA/BMI and SPI, while DEC/CMI will see northwest winds after
fropa of 01-02z. Winds will increase with gusts of 20-23kts
tomorrow and then diminish in the afternoon.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Auten
SHORT TERM...Geelhart
LONG TERM...Geelhart
AVIATION...Auten
Area Forecast Discussion
National Weather Service Northern Indiana
812 PM EST Thu Feb 15 2018
.SYNOPSIS...
Issued at 258 PM EST Thu Feb 15 2018
Light rain and areas of fog will continue through the early evening
with dry and cooler conditions anticipated by late tonight.
Temperatures tomorrow will hover around freezing. There is a chance
of light rain or snow late Saturday with another...much
better...chance for widespread rain Monday into Tuesday. After a
seasonably cool weekend...temperatures warm back up for early next
week.
&&
.UPDATE...
Issued at 800 PM EST Thu Feb 15 2018
Frontogenesis forcing in association with sfc trough dropping
across northern Indiana, highly anomalous PWATS, and highly
sheared mid/upper level trough have been sufficient for some
isolated convection across north central/northeast Indiana this
evening. This convection has developed in highly sheared
environment with lifted parcel levels relatively shallow which has
allowed these cells to tap into elevated instability. Instability
magnitudes are quite limited however, and have mentioned an
isolated 40 mph wind/small hail threat over next half hour for
far eastern Jay county. Isolated storm may reach far southern
portions of Allen County Ohio but more limited instability with
northward extent will likely limit this potential.
Otherwise, in terms of fog, have seen some improvements in vsbys
across portions of the dense fog advisory this evening, although
several sites are still reporting one quarter mile vsbys. Would
expect that patches of dense fog will persist for the next hour or
two before steadier improvement late evening/early overnight as
drier low level air works southeast. Will allow current dense fog
advisory to carry through to the 03Z expiration.
&&
.SHORT TERM...(This Evening through Friday)
Issued at 258 PM EST Thu Feb 15 2018
Intensifying upper level jet and associated low level fgen response
spreading light rain across the area. A few thunderstorms noted
upstream earlier but appears stable enough locally to preclude any
thunder in our area. Rain and snowmelt due to warm/moist air has led
to slow improvement in visibilities on southern fringes of advisory
as expected. Will drop a few counties but lack of rain and deeper
snowpack across our far NW could maintain dense fog through the
evening as suggested by latest HRRR and RAP. Have therefore extended
the advisory for those areas. Do expect improvement everywhere
overnight though as front passes and winds switch around to the
northwest. Rain will also end by late evening. A few lake effect
snow showers may be possible Fri morning but instability is very
marginal with 850mb temps only around -10C, low inversion heights,
and increasing dry air advection. Doubtful of anything measurable
but no qualms with inherited 20 PoP. Postfrontal CAA will lead to
lows dipping into the 20s with highs tomorrow only in the low/mid
30s.
&&
.LONG TERM...(Friday Night through Thursday)
Issued at 258 PM EST Thu Feb 15 2018
After a seasonably cool and dry Sat morning, next shortwave arrives
late Sat. Midlevel CVA is decent but upper level jets are poorly
aligned with lackluster moisture return locally. Maintained just
chance PoPs with very light QPF. Expect a rain/snow mix with surface
wet bulb temps hovering in the low 30s. Little/no accumulation or
impacts expected.
Temps then rebound heading into early next week as next longwave
trough approaches. Deep SW flow develops and spreads ample
warm/moist air into the region. Highs could easily make a run at low
60s on Mon and Tue. Widespread rain also expected during this
time...though exact details on timing and amounts remain uncertain.
Will continue to watch this period for potential flooding concerns
given recent snowmelt/wet conditions. Cooler for the end of next
week but nothing unusual for this time of year with overall mild
pattern for the foreseeable future.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
Issued at 651 PM EST Thu Feb 15 2018
A series of sheared upper vortices continue to track across the
southern Great Lakes region this evening. Passage of these vorts
has allowed for slow but steady southeast progression of low level
front. Low level fgen forcing combined with weak elevated
instability has been sufficient for continued generation of
showers across northern Indiana late afternoon/early evening.
By the overnight hours, focus for additional showers and
thunderstorms should begin to shift southeast of the terminals.
Widespread fog has been the other concern over the past 24 hours,
particularly at KSBN where greater snowmelt has occurred. Should
gradually see vsbys improve at KSBN over next few hours as front
continues to slowly sag southeast. A period of LIFR conditions
still possible over next few hours, but cigs should improve to
above fuel alternate criteria overnight as drier low level air
works in from the northwest. A secondary trough will bring
reinforcing cold air advection for Friday morning, and steep low
level lapse rates should allow MVFR cigs to persist into Friday
before scattering later Friday afternoon.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Dense Fog Advisory until 10 PM EST /9 PM CST/ this evening for
INZ003>007-012-014.
MI...Dense Fog Advisory until 10 PM EST this evening for MIZ077>081.
OH...Dense Fog Advisory until 10 PM EST this evening for OHZ001-002.
LM...NONE.
&&
$$
UPDATE...Marsili
SYNOPSIS...AGD
SHORT TERM...AGD
LONG TERM...AGD
AVIATION...Marsili
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Area Forecast Discussion
National Weather Service Charleston WV
958 PM EST Thu Feb 15 2018
.SYNOPSIS...
Unseasonably mild, moist air in place, until a cold front
crosses early Friday morning. High pressure Friday night. Low
pressure late Saturday/Saturday night. High pressure Sunday.
&&
.NEAR TERM /THROUGH FRIDAY/...
As of 10 PM Thursday...Added the mention of a slight chance of a
thunderstorm. Instability should remain just strong enough
overnight to see some embedded thunderstorms into early Friday
morning.
As of 825 PM Thursday...Tweaked PoP again with this update.
Shower activity is becoming more widespread in Ohio just out
ahead of the approaching cold front and will be progressing
eastward of the next few hours. This front is oriented from WSW
to ENE and it is very slowly moving to the SE. As such, heavy
rainfall will move very slowly across the region late tonight
and through Friday morning out ahead of the front. The cold
front will press across SE Ohio around sunrise and eventually
reach our eastern mountain counties by Friday afternoon. Still
looking at widespread rainfall amounts of 1 to 2 inches across
the Northern CWA and about an inch in the south.
As of 330 PM Thursday...Updated PoP through midnight with main
swath of rain generally to the north through then. However,
isolated to scattered showers will be possible across the south
this evening, but much lower chances here. Thereafter, went
with a HRRR Ensemble method for PoP through the overnight as
the front progresses southward into Friday morning.
As of 200 PM Thursday...
The airmass at the low levels continues saturated causing low
clouds and periods of rain showers. Radar images show the
rainfall activity has moved north across PA and WV border.
However, more scattered showers are evident on ILN radar, moving
east toward our area. Expect these rain showers to affect
southeast OH and portions of WV by 21Z. Models suggest plenty of
QPF mainly across the northern third of the area. In fact, WPC
has the same area under Slight risk for excessive rainfall
Friday. A cold front will squeeze the available moisture into
moderate to heavy rain showers. With the soils already
saturated, and some rivers or streams have reacted from previous
rain, the threat for river flooding continues. Therefore, the
Flood Watch remains in effect through Friday evening.
Low temperatures tonight will be warm, in the mid to upper 50s.
The high temperatures forecast for Friday will occur during the
early morning hours, with a non-diurnal trend under cold air
advection through Friday afternoon and evening.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
As of 230 PM Thursday...
By Friday night, maybe just a few upslope snow showers across
the mountains, but overall things will be fairly quiet. Rain
will push back into the area on Saturday as another wave of low
pressure moves east. Guidance is in fairly good agreement now
with keeping the heaviest rain with this across SW Virginia and
Eastern West Virginia. These areas were recently hit hard just
last weekend with over 3 inches of rain, so although this
system should only drop a half inch to an inch of rain, it could
still cause some problems due to the wet antecedent conditions.
Also, in the mix with this system will be the cold air hanging
around in the Northern West Virginia Mountains for wintry
precipitation to fall. Expecting to see a wintry mix with
possibly just all snow in the higher elevations. 2 to 4 inches
of snow is not out of the question for the highest terrain and
some icing with a freezing rain/sleet mix will also be possible.
High pressure builds back in over the area on Sunday and brings
at least a brief period of dry conditions to end the weekend.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 245 PM Thursday...
Forecast guidance really diverges after Sunday. Ensemble and
operational guidance does keep on the periphery of a Bermuda
High pressure, with very warm conditions expected with deep
southwesterly return flow. This will also keep plenty of
moisture readily available in the area, but timing and tracks of
several waves next week will determine how wet the forecast is.
GFS is currently much more active and wet than the Euro through
the week, with several waves pushing through the area. With the
uncertainty, have leaned heavily on a blend of ensemble and
operational guidance for the long range forecast. Will have to
continue to monitor as we head into next week, as the pattern
does suggest that more heavy rain and flooding could be
possible.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
As of 640 PM Thursday...
Cold front will be pushing through the region overnight and
bring periods of heavy rainfall. Confidence on timing of heavy
rain and impacts at specific TAF sites is still fairly low at
this time. However, IFR conditions are expected as the heaviest
swath of rain moves through early Friday morning. Conditions
will eventually improve to MVFR in the lighter rainfall behind
the front.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SATURDAY...
FORECAST CONFIDENCE: Low.
ALTERNATE SCENARIOS: Timing of category changes will likely vary
and is dependent on heavy rainfall.
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 FRI 02/16/18
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 M M M H H H M M H H H L
HTS CONSISTENCY M M M M M M M M M M M L
BKW CONSISTENCY M M M H H H H H H M L L
EKN CONSISTENCY M M M M H H H H H M M M
PKB CONSISTENCY M M L L M H M M M L M L
CKB CONSISTENCY L L L L L L H H L L M L
AFTER 00Z SATURDAY...
Periods of IFR possible in rain, fog and/or stratus early Saturday
and Saturday night.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...Flood Watch through Friday evening for WVZ005>011-013>020-
024>034-039-040-515>526.
OH...Flood Watch through Friday evening for OHZ066-067-075-076-
083>087.
KY...Flood Watch through Friday evening for KYZ101>103-105.
VA...Flood Watch through Friday evening for VAZ003-004.
&&
$$
SYNOPSIS...ARJ/MPK
NEAR TERM...ARJ/MPK
SHORT TERM...MPK
LONG TERM...MPK
AVIATION...ARJ
Area Forecast Discussion
National Weather Service Tucson AZ
225 PM MST Thu Feb 15 2018
.SYNOPSIS...Showers will gradually decrease in coverage into
tonight. However, scattered showers will return Friday afternoon and
evening, especially east and south of Tucson. Dry conditions with
warmer temperatures will then prevail Saturday. Another disturbance
is expected to bring a slight chance of showers to much of the area
early next week.
&&
.DISCUSSION...The main area of rain continued to shift farther east
and diminish in coverage this afternoon. Will maintain this trend in
the forecast for tonight. Latest HRRR model showed just a few
showers lingering across the area after 16/06Z, but extensive cloud
cover remaining over southeast Arizona through tomorrow evening.
Thus, low clouds and patchy fog can be anticipated overnight and
early tomorrow. Daytime temperatures will start to recover this
weekend back to more seasonable readings. Overall, the latest models
indicated a dry forecast for the weekend before another system
tracks through the region early next week. For now, looking a the
best chance of showers remaining east and south of Tucson.
Thereafter, models showed a stronger system impacting the region
late next week into next weekend.
&&
.AVIATION...Valid thru 16/18Z.
Cloud layers SCT-BKN 3-6k ft AGL and several BKN-OVC layers above,
with SCT SHRA tonight. Occasional MVFR and ISOLD IFR cigs and vsbys
with mountains obscd, especially through early Friday morning. Sfc
wind generally south to southwest at less than 12 kts through the
period. Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Showers will continue to decrease in coverage
tonight into tomorrow. Saturday is expected to be dry everywhere
then a small chance of showers returns to the forecast late Sunday
through Monday night. Light winds expected through Saturday then an
increase in SW winds should occur Sunday and even more so on Monday,
however fuel moisture levels will be much improved by that point and
RH levels will remain relatively high.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
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