Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/02/19
Area Forecast Discussion
National Weather Service Bismarck ND
857 PM CST Fri Feb 1 2019
.UPDATE...
Issued at 855 PM CST Fri Feb 1 2019
Getting some flurries across the north this evening with the
advancing cold air so added them to the forecast tonight/tomorrow
morning in addition to the patchy to areas of fog.
UPDATE Issued at 542 PM CST Fri Feb 1 2019
Mid to high clouds have overspread most of west and central North
Dakota so will increase cloud cover for tonight. Lower stratus
moving south along the Canadian border and expect their arrival
across the northern sections of the state this evening, which is
associated with cooler air. Current forecast looks good.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 230 PM CST Fri Feb 1 2019
Forecast highlights in the short term period will be continued
mild temperatures tonight and Saturday, with areas of fog tonight.
Currently, broad ridge across the Rockies into the Great Plains
results in zonal flow aloft over the region. Surface warm front
over the central Dakotas with a cold front draped just north of
the International border with low pressure centered over central
ND. Very mild temperatures behind the warm front with 40s west
and south central. Colder along to east of the front with
temperatures in the 20s across my far east. Mid to upper level
cloud cover increasing west into central.
Surface cold front drops southward tonight as sfc low moves
southeast, bringing with it a surge of low level stratus and
likely fog development. Both the RAP & HRRR show this development
in the evening/overnight hours. Dense fog will be very possible
northwest into central and portions of the southwest, and will
monitor for possible dense fog headlines tonight/Sat AM.
Another area of sfc low pressure develops and moves into eastern
MT/western ND Sat, developing with it another warm frontal zone
which looks to bring enough WAA into my southwest with mid/upper
40s again possible. The WAA tomorrow will be confined to my
southwest, with teens and 20s elsewhere for highs on Saturday.
.LONG TERM...(Saturday night through Friday)
Issued at 230 PM CST Fri Feb 1 2019
Highlights in the long term period will focus on a potential
winter storm moving into the area late Sat night and impacting the
region Sunday and Sunday night. This will be followed by an
extended period of cold.
12Z models and associated WPC guidance have come in wetter with
QPF, which closely matches trends with GEFS plumes which have
clustered higher. QPF now looks to be fairly widespread 0.4 -
0.6", about a tenth to 0.15" higher than the last couple of model
cycles. Collaborated modifying snow ratios with the strong CAA.
This combined with the wetter trend has added around 2" of
snowfall to our forecast for the Sunday/Sun night period. This
now puts 6-9" north of I94, and 3-5" south for storm total
amounts. After a collaboration call with WPC and local
collaboration with FGF, we have opted to issue a winter storm
watch. Will include the entire area for a couple of reasons. First
to account for any further southward trends, and second to
account for the blowing snow potential southeast. The watch will
be valid from 12Z Sunday morning until 12Z Monday morning.
There is definitely the possibility of snowfall totals coming
down given the progressive nature of the S/WV, though hard to
ignore the trend for higher QPF (and the great agreement amongst
models with such) and the higher snow ratios, so we along with WPC
and our western and eastern neighbors feel the watch is
justified. Upper level jet dynamics associated with a jet streak
lifting northeast across out region will see the strongest lift
Sunday morning/afternoon. The overall threat for heavy snow
banding still appears low given the lack of favorable midlevel
frontogenesis and mid level lapse rates advertised. Blowing snow
will be maintained in the forecast, especially Sunday night-
Monday AM when models show strong northerly winds on the backside
of the sfc cyclone.
Afterwards, confidence remains high in wind chill hazards next
week with the multi-model consensus also supporting highs below
zero Monday through Thursday. Another opportunity for snow remains
in the forecast on Tuesday and perhaps on Thursday associated
with fast moving S/WV`s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 542 PM CST Fri Feb 1 2019
A Cold front lying across northern North Dakota at 5 PM CST will
move south tonight and Saturday. Deteriorating conditions from
VFR to MVFR to IFR will follow the front due to low clouds and
areas of fog.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
Winter Storm Watch from Sunday morning through late Sunday night
for NDZ001>005-009>013-017>023-025-031>037-040>048-050-051.
&&
$$
UPDATE...WAA
SHORT TERM...NH
LONG TERM...NH
AVIATION...WAA
Area Forecast Discussion
National Weather Service Charleston SC
957 PM EST Fri Feb 1 2019
.SYNOPSIS...
High pressure will prevail to the north tonight. Weak upper
level disturbances are forecasted to affect the area this
weekend. High pressure will then build across the region and
persist through late next week.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Late this evening: Not much change to the previous forecast.
Radar imagery shows that light precipitation is filling in
nicely just to the south of the forecast area, and a number of
observations sites are reporting light rain. However, recorded
rainfall amounts are just a hundredth of an inch or so.
Increased rain chances along and south of I-16 for the next
several hours, but still don`t expect much if any rainfall
accumulation. Overall, the new 02/00z NAM seems to be
initializing the best while the hi-res RAP and HRRR seem to be
struggling to capture the coverage of light rainfall. Previous
discussion continues below.
Early this evening: Surface analysis shows high pressure over
the Atlantic extending back across the forecast area with a
nearly stationary frontal zone well to the south that runs west
to east across the Gulf of Mexico. Surface observations are
hinting at the beginnings of a coastal trough, mainly across the
Georgia coastal waters where winds have turned northeasterly.
Radar imagery shows very light returns moving into southeast
Georgia, though it does not appear that anything is reaching the
ground. A notable precipitable water gradient exists across the
forecast area, with values down around half an inch near Lake
Moultrie, and values of an inch or greater just to the south of
I-16. So, considerable dry air remains in place and will need to
be eroded away before rainfall becomes too widespread. This
will likely keep most land areas dry through sunrise, with the
exception being southeast Georgia mainly along and south of
I-16. The driver for precipitation development is a well defined
mid-level shortwave tracking eastward along the Gulf Coast. For
now, some confluence just to the north is maintaining the dry
air. By sunrise Saturday, PVA will spread in from the southwest
associated with the trough, and weak cyclogenesis will begin
just off the north Florida coast. Models continue to struggle
with this setup, with hi-res solutions like the HRRR and RAP
showing virtually no rainfall through tonight while the
GFS/NAM/ECMWF all show some degree of precipitation breaking out
across the southwest periphery of the forecast area. Tried to
create a blend of the two camps in rain chances, at least until
radar trends become more apparent. Overall, made some
adjustments to rain chances, but most other parameters did not
need significant adjustments.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
Saturday: A mid-level short-wave with some vorticity embedded
within it will move over our area from the morning into the
afternoon. A second, stronger short-wave will approach from the
west in the evening, reaching our area by daybreak Sunday. At
the surface, high pressure over the Mid-Atlantic states in the
morning will retreat while a coastal trough strengthens
over/along the FL east coast. The bulk of the energy with this
feature is forecasted to remain just offshore. However, the
feature itself should brush our coastline into the afternoon
hours, moving to the northeast along the coastline into the
overnight hours. The bulk of the moisture will remain far
offshore. Though, PWATs across our area will generally be above
1". Factoring all these variables, we have likely POPs brushing
along the coastal counties during the day, tapering as one heads
inland. The QPF reflects this. Though, rainfall amounts won`t
be substantial. Highs will be a few degrees above normal, while
lows remain very mild. One thing to note is if the position of
the trough moves further inland than expected, then a
substantial change to the POPS and QPF would be needed.
Sunday: A mid-level short wave will be over the Southeast in
the morning. This wave is forecasted to slowly move eastward
during the day while amplifying. It is forecasted to develop
into a low as it moves offshore overnight. At the surface, a
coastal trough will generally be brushing along northern
portions of our area in the morning. This feature will move away
during the day, accelerating to the northeast into the night.
At the same time, high pressure initially over the Mid-Atlantic
states will gradually build southwards into the evening and
overnight hours. The highest moisture will be located near
Charleston in the morning, gradually lowering into the day and
especially at night. POPs are generally in the chance category
during the day with only a few hundredths of QPF expected.
Conditions are expected to dry out overnight with gradually
clearing. Highs will once again be a few degrees above normal.
Lows will be above normal too. Though, not as warm as the
previous night due to some clearing.
Monday: The mid-levels will consist of a strengthening low off
the Southeast coast. This low will be pushed away by building
heights within semi-zonal flow over our area. At the surface,
high pressure will be over the Southeast. In the Atlantic will
be a departing low/trough. To the west will be a distant,
approaching front. The high will dominate the forecast, bringing
dry conditions with some clouds. The airmass does start to
moderate, with highs rising about ten degrees above normal.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A drier and warmer pattern is anticipated heading through at
least the middle of next week as sfc high pressure settles over
the Southeast under a ridge of high pressure building aloft. In
general, afternoon temps should peak into the low 70s Tuesday,
then mid 70s Wednesday and Thursday well ahead of a front
approaching northern areas next weekend. Overnight lows will
also trend warmer a few degrees each night, from the upper
40s/lower 50s Monday night to mid/upper 50s by Wednesday night.
Although a few showers are possible across inland areas mid
week, the best chances of precip appear to be next weekend
should a front shift into the region. There is also a low threat
of sea fog moving onshore into the immediate coastal areas mid
to late week as light southerly winds and sfc dewpts approach 60
degrees over cooler shelf waters.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
VFR conditions should prevail through the overnight period.
Then on Saturday, the chance for MVFR ceilings increases through
the day as an area of low pressure develops offshore. Have
started MVFR ceilings at KSAV at 13z and also brought in some
showers by around midday. Guidance for KSAV would suggest that
IFR ceilings will start in the afternoon, but confidence isn`t
high enough to introduce quite yet. Instead, the forecast
features low end MVFR for the latter part of the period.
Ceilings will be slower to arrive at KCHS, and for now the
forecast period is VFR. Did introduce a VFR ceiling at 20z, and
as we get closer to 00z Sunday the chances for MVFR or lower
will increase at KCHS as well.
Extended Aviation Outlook: Weak upper level disturbances along
with a coastal trough could bring periods of flight restrictions
Saturday into Sunday. VFR will prevail Monday through
Wednesday.
&&
.MARINE...
NE flow will gradually strengthen overnight as the coastal
trough strengthens off the FL/GA coast.
Weak upper level disturbances are forecasted to move over the
region this weekend. This will cause a coastal trough initially
along the east coast of FL to move northeastward, passing along
our coast Saturday. The trough should continue it`s movement to
the northeast and away from our area on Sunday. Winds are
expected to be at their strongest Saturday, sustained at perhaps
no more than 15 kt across the waters. Winds should then ease a
few kt Sunday. Inland high pressure will build on Monday,
causing winds to veer with speeds at or below 10 kt. Seas will
generally range between 2-4 ft into early next week, but we
could see waves as high as 5 ft in the offshore GA waters late
Sunday. High pressure should then extend across the waters by
Tuesday, then persist into the middle of next week. Winds and
seas will remain well below Small Craft Advisory levels during
the transition, but light southerly winds should develop heading
into mid week. These winds along with dewpt temps approaching
60 degrees, could become more favorable for sea fog over cooler
shelf waters mid week.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.
&&
$$
NEAR TERM...BSH
SHORT TERM...MS
LONG TERM...DPB
AVIATION...BSH/MS
MARINE...JRL/MS
Area Forecast Discussion
National Weather Service Sioux Falls SD
556 PM CST Fri Feb 1 2019
.SHORT TERM...(This evening through Saturday)
Issued at 335 PM CST Fri Feb 1 2019
Difficult temperature forecast for the next few days with strong
inversion across the area. NAM is very aggressive with near surface
moisture from melting snowpack, and has widespread fog developing
overnight tonight. GFS and HRRR suggest the potential developing
across western Iowa, and lifting north into the forecast area early
on Saturday morning. Have patchy fog mention across the south, but
think it will be fairly shallow except for northwest Iowa. Have
lingering mention of fog across northwest Iowa Saturday morning.
Where fog/stratus clear on Saturday, should be a nice day with 925
hpa temperatures warming towards 10C. Won`t be able to realize the
full value of warming, but have raised forecast highs in the south-
especially where snow cover has cleared.
Potential for fog and stratus continues to plague the forecast area
Saturday night, especially in the east. Have added mention of fog
and increased sky cover Saturday night into Sunday.
.LONG TERM...(Saturday night through Friday)
Issued at 335 PM CST Fri Feb 1 2019
Warm front lifts north on Sunday towards the I-90 corridor. Stratus
is expected to increase in depth throughout the day ahead of the
next approaching low. With strong lift above the surface, could see
drizzle/freezing drizzle develop, especially during the evening
hours Sunday night as isentropic lift increases. Dry layer in the
mid levels of the atmosphere makes the dendritic layer difficult to
utilize, and as such, looks like a drizzle/freezing drizzle event
ahead of cold front moving through late Sunday night. Forecast
highs on Sunday will be key, as locations north of I-90 look to
mainly remain below freezing. With the increasing lift Sunday
evening, could see an icing event develop. Right now best chances
for significant icing appear to be across southwest Minnesota.
Have raised icing amounts there to 0.1-0.15", and will heighten
wording in the HWO.
With the passage of the front, expect northwest winds to rapidly
increase and precipitation to quickly transition to snow. Lift
quickly pulls away from the region on Monday morning and the region
is left with strong and gusty winds. Have raised winds by blending
in MOS values.
Tuesday into Wednesday continues to look active with unsettled
pattern across the area. A series of waves look to work through the
region possibly creating periods of light snow across the region.
This threat looks to continue till Arctic front works through the
region Wednesday night. Behind the front, much colder air works
into the region. Will likely need a wind chill advisory for much of
the area as wind chills hover in the 15 to 30 below range much of
late next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 555 PM CST Fri Feb 1 2019
Clear skies and light winds will continue overnight. During the
early morning hours, there is a chance of fog development. This
is not a high confidence situation, given continued light surface
winds in the 5 to 10 kt range may promote marginal surface
mixing, but with snow melt during the daytime hours, the boundary
layer is likely moist enough to create at least patchy fog. Those
in northwest Iowa have the highest chance for more widespread
fog, given more robust moisture advection. By 02/1600z, daytime
mixing should be sufficient to dissipate any fog.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
SHORT TERM...BT
LONG TERM...BT
AVIATION...VandenBoogart
Area Forecast Discussion
National Weather Service Huntsville AL
909 PM CST Fri Feb 1 2019
.NEAR TERM...(Tonight)
Issued at 909 PM CST Fri Feb 1 2019
An interesting forecast continued to unfold across parts of the area
this evening. A plume of mid level moisture present in a west to east
orientation across southern Tennessee was actually causing light
showers via local radars from east of Memphis, along the MS/TN
border, across middle Tennessee (so far north of Lincoln, Moore and
Franklin counties). Only trace amounts of rain have been noted from
the very few rainfall reports received near Memphis, suggesting most
of it was remaining aloft. The bad; none of the recent models were
really picking up on this light rain.
However, moisture and relative humidities in the low/mid atmosphere
at 7000-10000 ft were supportive of this. The 290-295K isentropic
region from the RAP and NAM nicely indicated this; but did not
reflect precipitation as a result. Those models also indicated that
the moisture should downglide/fade during the course of the late
evening and overnight (something the models may be accounting for),
thus this should only be a short term affair. The RAP was drying the
295K region faster than the NAM.
We have added a slight chance of showers for parts of our middle TN
group given how close the showers are. Again, rain chances should
fade during the overnight as drier air works in from the ESE. Given
a return to a more zonal pattern and warmer atmosphere, not as cold
night time lows are forecast. Night time lows in the mid/upper 30s
are expected, with maybe a spot or two briefly freezing before
sunrise on Saturday.
.SHORT TERM...(Saturday through Sunday)
Issued at 237 PM CST Fri Feb 1 2019
Tomorrow, a shortwave will weaken as it moves across TX and the
Southern MS Valley. Moisture however will increase ahead of this
feature. Dewpoints will return to the 40s on Saturday and the 50s by
Sunday. Even though there will be some moisture return on Saturday,
forecast soundings are still pretty dry so continued to keep precip
out. The shortwave will move across the TN Valley Saturday night,
bringing additional moisture with it, thus additional cloud cover.
Models disagree with how much rain we could receive (or any at all)
on Sunday/Sunday night due to how they are handling the shortwave and
ridge building in behind it, so went with a slight chance for most
of the CWA at this time. Look for above normal temps through the
weekend! Daytime highs will reach the lower 60s on Saturday with
overnight lows in the lower 40s. Although heights will rise on
Sunday, cloud cover will keep daytime highs in the lower 60s but
overnight lows a little warmer in the mid 40s to lower 50s. For
reference, our normal high temps are in the lower 50s for this time
of year.
.LONG TERM...(Sunday night through Thursday)
Issued at 237 PM CST Fri Feb 1 2019
Next week, the medium range models are in fair agreement that a
large scale 5h ridge will build across the Gulf of Mexico through the
FL peninsula and Bahamas. They diverge on the strength of the ridge,
with the operational GFS being most dominant over the FL peninsula.
The ridge will produce persistent southwest to westerly flow across
much of the southern CONUS, and either shearing or limiting the
southward latitude of trough progressions across the central and
northern CONUS. The ECMWF is still pushing the arctic front southeast
through on Friday (day 8). At this point, favoring the GFS given the
upper pattern which may keep the local area in a warm sector airmass
for the entire week. Blended guidance will temper the warm sector by
Thu night-Fri in our NDFD forecast however, so this is subject to
change...alot! On Tuesday a very shallow cool air may temporarily
reach southern TN or north AL before lifting right back north Tuesday
evening. But then the arctic boundary may remain far enough
northwest Wed and Thu to keep the area rather rain-free. Will keep
blended guidance for PoPs, but these are relatively low chances. And,
given instability increasing, won`t rule out a few thunderstorms
Wed-Thu. The heaviest rain band will likely be to our northwest this
forecast however. Highs could easily reach the u60s-l70s next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 552 PM CST Fri Feb 1 2019
An area of mid level clouds ~7-9 kft were in a west-east axis across
southern TN. Some of the clouds over western/middle TN had ceilings
down to MVFR ~2-3kft. Forecast trends have these mid-level clouds
becoming scattered in the overnight. Otherwise, scattered high
altitude clouds are possible after daybreak on Sat. Winds through the
TAF should remain light, mainly from the SE in the 2-5kt range.
&&
.HUN WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
TN...NONE.
&&
$$
NEAR TERM...RSB
SHORT TERM...JMS
LONG TERM...17
AVIATION...RSB
For more information please visit our website
at weather.gov/huntsville.
AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
952 PM EST Fri Feb 1 2019
.SYNOPSIS...
High pressure centered to the east will provide dry weather
tonight. Dry weather is forecast to continue through Saturday
and Sunday as the high settles along the Atlantic Coast. Rain
showers are expected Monday along a weak cold front traveling
from the west.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Patches of stratocumulus over the area have mostly dissipated or
moved east, though one area of 2kft-3kft clouds remains parked
over Wilmington. Just south of the ILN forecast area (and along
the southern border) is an area of lower stratus clouds,
generally below 1500 feet in height. These clouds have begun to
expand, and visibilities have been dropping below them, and
especially along their periphery in the Louisville.
On the 00Z KILN sounding, discounting the slight bit of moisture
associated with the stratocumulus, the moisture lower in the
sounding (below 950mb) is rather shallow. There remains an
expectation that fog and stratus will move into the area during
the overnight hours, generally spreading in from the
southwestern sections of the CWA. What makes the forecast a
little bit uncertain is that there are discrepancies between
the current observations and the way the HRRR (usually a very
useful model for fog development) is depicting the scenario. The
21Z SREF fog probabilities actually seem a better fit for the
current scenario. These suggest that fog will overspread most of
the forecast area, but the potential for significantly reduced
visibilities may be most prevalent in the western third of the
CWA. Given that this is not really a pure radiation fog scenario
(with theta-e advection beginning on light southeasterly flow)
the lack of moisture further east and northeast may limit fog
potential to some degree.
Temperatures and dewpoints are generally expected to remain
steady for a few hours, then rise as the rest of the overnight
period goes on. No major changes were required to the previous
forecast, outside of lowering sky cover to account for current
conditions.
Previous discussion >
Surface analysis shows high pressure centered over Lake Erie.
Given the subsidence and lack of forcing and deep moisture
around the high, there should be no precipitation tonight as
the high moves to Pennsylvania.
However, models, observations and satellite imagery show
persistent clouds due to moisture trapped under an inversion
around 1000 ft AGL. In addition, fog may form as slightly warmer
air advects over snow cover. Mitigating factor for dense fog
will be winds staying above calm as the pressure gradient
becomes more prominent later tonight behind the high.
Overnight lows will be tricky due to the balance between warm
advection and cold snow cover. We should see readings fall off
to the teens and twenties early this evening, before a modest
rebound later tonight brings temps up into the 20s across the
area.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
High pressure will settle along the Atlantic Coast on Saturday.
With models showing a nearly saturated boundary layer and a
persistent low level inversion, cloudy skies are likely to
persist. No precip is expected in a regime still lacking forcing
and deeper moisture. Fog will be possible again Saturday night
due to continued warm advection over snow.
Temperatures may rise to the 30s and 40s by late Saturday
afternoon. However, went below guidance because warmer readings
will be hard to attain due to cold ground and cloud cover.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
Sunday temps are forecast to rise a bit faster than previously
forecast once any lingering fog burns off within a few hours of
sunrise. Still expect many areas to see temps rise into the low to
mid 50s by mid afternoon, but now expecting slightly cooler
conditions for Sunday night. Maintained a dry forecast during the
day and overnight attributed to southern Appalachia high pressure
influence and veering surface winds. Only expecting some 850 mb
clouds instead of precip potential beneath an increasingly muted mid
level shortwave.
Still on track to see low pressure progress toward the Great Lakes
on Monday brining showers along and ahead of a trailing cold front.
Winds will pick up mid morning ahead of the front as the surface
pressure gradient tightens up by 15Z producing gusts to around 20-25
kt. WAA will be weaker on the warm side of the front causing
temperatures to be a bit cooler than the last forecast update. The
first wave of showers still appears coupled with a pre-frontal
surface trough with an earlier arrival of the front. GFS still more
bullish on QPF, thus maintained blended pops. No significant changes
in thunder potential which still appears low. One interesting
feature that is becoming more defined is a stronger 850 mb jet
intersecting the through which could slightly extend the duration of
the trailing precip.
Tuesday will see a return to CAA advection pattern from stronger NW
flow as surface diffluence sets up from a developing lee-side low
along the Rockies in conjunction with anticyclonic flow from
eastward traversing Canadian high pressure to the north. The high
does seem to be slowing along its Atlantic heading which will
increase the duration of dry air persistence ahead of the advancing
system potentially delaying the onset of precipitation. This would
help increase the chance for wintery form precip. Delayed higher
pops a smidge ahead of the precip shield due to the drier air out
ahead. Coverage of showers will expanded throughout the late
overnight becoming more widespread by daybreak.
Models have come in colder behind Tuesday`s cold frontal passage. As
such, embedded short wave energy and return moisture flow may bring
some wintry pcpn to northern sections by Tuesday night into
Wednesday morning before temperatures warm enough into Wednesday
afternoon. Even so, east/southeast flow, clouds, and pcpn chances
increasing on Wednesday will keep temperatures down some, especially
north. Forecast highs will range from the upper 30s north to the
lower 50s far south.
Models are keying on a mid level trough to move from the
northern/central Plains into the Great Lakes and Ohio Valley for the
period Wednesday night into Friday. This process will bring a wave
of low pressure through the region along with the likelihood of
pcpn. In addition, forecast pwats are concerning with various
outputs forecasting 1 to 1.50 inches moving into the Ohio Valley.
This may pose a flooding concern to the region, so we will be
keeping a watch and will update the forecast accordingly. Still a
little to early for the HWO, but later forecast may dictate this be
placed in this product. There may be a chance of thunder with the
low, but placement differences preclude placing it in the forecast
at this time. Colder air advecting into the region Thursday night
into Friday may chance the rain to snow before tapering off. A blend
of models have been used for a non-diurnal cycle period. Highs on
Thursday are forecast to range from the lower to mid 40s far
northwest to near 60 southeast, cooling to highs from near 30
northwest to the near 40 southeast on Friday
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
The main concern through the forecast period is the potential
for fog overnight.
MVFR ceilings currently in place have been breaking up, and a
period of prevailing VFR conditions is expected to occur for all
of the TAF sites. As the night progresses, however, visibilities
will begin to drop. There is high confidence in reduced
visibilities of MVFR to IFR, with slightly less confidence in
how low the visibilities will get. However, there is at least
some potential for dense fog, particularly for KCVG/KLUK/KDAY.
Some MVFR/IFR ceilings may also develop during this time frame,
though for the most part the aviation conditions should be
dictated by the visibilities.
Whatever fog develops should be slow to improve on Saturday
morning, though eventually visibilities should get to VFR at all
sites (though MVFR ceilings may persist). Going into Saturday
night, there is some potential for fog and low ceilings to
develop again.
Winds through the TAF period will start out from the east to
southeast, and will shift to the south / southwest by Saturday
morning. Speeds are expected to remain at or below 10 knots.
OUTLOOK...MVFR/IFR conditions are expected to continue into
Sunday. MVFR conditions are possible again at times from Monday
through Wednesday.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...Coniglio
NEAR TERM...Coniglio/Hatzos
SHORT TERM...Coniglio
LONG TERM...Hickman/KK
AVIATION...Hatzos
Area Forecast Discussion
National Weather Service Marquette MI
652 PM EST Fri Feb 1 2019
.SHORT TERM...(This evening through Saturday)
Issued at 244 PM EST FRI FEB 1 2019
Water vapor imagery and RAP analysis shows a shortwave moving ese
from northern Manitoba toward James Bay. WAA ahead of this feature
and its sfc low over ND has led to light snow over portions of
northern MN and NW Ontario this afternoon. WAA in sw flow under
mostly sunny skies has also allowed Upper Mi temps to rebound into
the double digits above zero this afternoon after overnight lows in
the teens to 20s below zero at many places (even a few spots has
mins of -30 or lower).
Tonight into Saturday, as a weak cold front sags southeast from
Ontario late this evening/overnight WAA ahead of it will spread
light snow into mainly the northern portion of Upper Michigan. With
models indicating the best forcing ahead of the Manitoba shortwave
staying well north into Ontario, any snow accumulations over our
area should be minimal (less than an inch) with the better chance
for accumulating snow across the Keweenaw Peninsula and eastern
Upper Michigan. Temperatures tonight shouldn`t drop too much due to
increasing cloud cover and mixing from southwest winds. Expect
readings from 5-12F, coolest inland.
Winds shifting light and northerly behind the front on Saturday will
keep cloud cover around, although air mass probably not cold enough
for lake effect other than maybe scattered flurries. Expect highs on
Saturday mainly in the lower to mid 20s.
.LONG TERM...(Saturday night through Friday)
Issued at 335 PM EST FRI FEB 1 2019
Focus remains on a light icing event Sat night into Sun and on a
potentially significant winter system Sun night through Mon.
Sat night and Sun:
WAA/isentropic ascent will lead to areas of
freezing drizzle Sat night into Sun (only over the E by afternoon).
Temps will be warming later Sat night through Sun, with highs in the
mid to upper 30s, but with very cold road surface temps drizzle will
continue to freeze to untreated roads even after air temps rise
above freezing. Accumulations are only expected to be very minimal,
but could lead to slick spots on untreated surfaces such as roads
and sidewalks.
Sun night and Mon:
A strong shortwave will drive a roughly 1000mb
surface low that will move from SW WI at 15Z Mon to near Lake Huron
by 00Z Tue. Models have fallen into decent agreement, with the GFS
being the overall favored solution at this time. Unfortunately, even
with decent agreement, the details are very dependent on exact track
and temperature profiles, so confidence in exact numbers and
impacts remains limited.
Current thinking is that the NW U.P. (very roughly NW of a line from
Marquette to Watersmeet) will see somewhere in the range of 4-7
inches of wet, heavy snow, with peak intensity from late Sun night
into Mon afternoon. This will be impactful from a standpoint of wet,
heavy snow falling heavily for a time. Areas just S of that line are
forecast to see a mix of light freezing rain and marginal amounts of
wet, heavy snow with peak intensity on Mon morning and afternoon.
The combo of snow and ice could be quite impactful with regard to
travel mainly. Doesn`t look like enough ice on elevated surfaces to
cause significant impacts outside of travel. Farther S (roughly
along and S of a line from Iron Mountain to Rock to Seney, the
forecast is for mainly rain with little to no snow. High temps are
forecast to be in the low to mid 30s, but any areas that see above
freezing temps will likely only see those for a couple hours or so.
Even when temps rise above freezing in those areas, ground surface
temperatures will remain below freezing, which will result in
continued freezing rain on roads and sidewalks. Precip type and
amounts are highly in question over roughly the SE half of Upper MI.
Snowfall is more certain over the NW half. Of course, any shifts in
the track or changes in airmass will result in significant changes
to the forecast, especially over the SE. There is potential for
freezing rain to be all snow over the SE as models have generally
been trending cooler with temp profiles. Will issue an SPS to
highlight this event as well as ice potential Sat night and Sun.
In addition to the precip that falls during the event, air temps
look to fall rather quickly from NW to SE as strong CAA kicks in
behind the system. Could see single digit temps over the NW by early
afternoon and all areas should drop into the teens by mid-evening
Monday. Any wet snow or liquid will flash freeze as the cold air
comes in, potentially adding additional travel hazards.
Blowing snow will develop along Lake Superior as winds pick up Mon
morning into Mon evening, then gradually diminish Mon night into Tue
morning.
Mon night through Fri: Generally looking at marginal lake effect
snow and potentially some system snow. The very cold airmass shown
by models yesterday is not as cold in current runs, but below normal
temperatures are generally expected.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 652 PM EST FRI FEB 1 2019
A band of -sn will brush the area this evening, most likely
affecting KCMX and perhaps KSAW. The period of -sn will be short,
only lasting a few hrs at most. At KCMX, conditions may fall to IFR.
Otherwise, VFR conditions and LLWS will likely prevail at
KIWD/KCMX/KSAW this evening. A weak cold front will drop s across
the area overnight and Sat morning. As it does so, expect MVFR cigs
to set in at all terminals. Some -sn/flurries will also occur at
KCMX.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 244 PM EST FRI FEB 1 2019
Winds stay below gales until Monday when northeasterly gales of 35
to 40 knots develop on the backside of a low moving through the
Upper Great Lakes. Gales subside by Tuesday morning. Where the lake
is ice free, heavy freezing spray will continue into tonight, before
subsiding this weekend as temperatures moderate. The heavy freezing
spray makes a return early next week.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Heavy Freezing Spray Warning until 7 AM EST /6 AM CST/ Saturday
for LSZ162-240>251-263>267.
Lake Michigan...
None.
&&
$$
SHORT TERM...Voss
LONG TERM...Titus
AVIATION...Rolfson
MARINE...Voss
Area Forecast Discussion
National Weather Service Nashville TN
740 PM CST Fri Feb 1 2019
.UPDATE...
FOR EVENING DISCUSSION.
&&
.DISCUSSION...
Radar imagery this evening shows numerous showers have developed
across our southern counties generally along a line from Linden to
Altamont. Have had to greatly increase pops across the area for
the evening as nearly all model guidance had a massive fail and
missed this shower activity. Exception is the HRRR and have
relied on it for guidance, which shows these showers gradually
winding down through the evening while the overall area of precip
lifts slowly northward, with some sprinkles possible after
midnight. Have also raised lows a few degrees for tonight due to
the widespread cloud cover. Updated grids and zones already out.
&&
.AVIATION...
00Z TAF DISCUSSION.
VFR conditions continue for BNA/MQY this evening, with CKV wavering
in/out of MVFR CIGS and CSV holding at IFR CIGS. The overall
trend will be for all sites to go MVFR late tonight, around 04z
or after. CIGS will eventually improve to VFR everywhere mid-
morning to mid-day on Saturday.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION......Shamburger
AVIATION........Schaper
Area Forecast Discussion
National Weather Service Tulsa OK
739 PM CST Fri Feb 1 2019
.UPDATE...
The main change this evening was to reduce PoPs and insert some
patchy fog. See discussion below.
&&
.DISCUSSION...
The transition from a cold regime to a warmer one continues
today. Temps and dewpoints continue to rise as low level southerly
flow persists, and cloud cover has been stubborn to go away.
While there will be breaks in the cloud cover here and there, this
forecast will maintain a mostly cloudy to cloudy wording. The
trends in the HRRR have backed down on the fog potential for
tonight overall. A stronger southerly 925mb wind exists tonight,
unlike last night, which could help keep the BL mixed just enough.
Nevertheless, some patchy fog was put in the grids for after
midnight. With no discernable signal in the short term data for
precip tonight, PoPs have been dropped. Updated text products
sent.
Lacy
&&
.PREV DISCUSSION... /Issued 532 PM CST Fri Feb 1 2019/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
MVFR ceilings will continue this evening for the eastern OK TAF
sites, with IFR conditions developing this evening for the
northwest AR terminals. There may fog again at the NW Arkansas
sites, along with patchy drizzle overnight into early Saturday
morning. South winds will increase by mid day Saturday, with gusts
to 15-20kt possible at some of the sites.
PREV DISCUSSION... /Issued 257 PM CST Fri Feb 1 2019/
DISCUSSION...
Upper low currently located over southern NM will continue to shift
east tonight into Saturday. Patchy areas of light drizzle and/or
light rain will remain possible through the Saturday before wave
weakens/shifts east of the region.
Strong southerly winds will likely develop on Sunday as cyclogenesis
develops along the lee of the Rockies. Broken/overcast conditions will
likely persist for much of the day, limiting gust potential to some
extent. At least a limited fire weather danger threat will remain but
increasing low level moisture will likely mitigate a more
significant threat.
Temperatures will remain well above normal Sunday into Monday night
ahead of next cold front that will move into northeast Oklahoma Monday
morning. Precipitation chances should remain low with frontal passage
as boundary stalls across southeast Oklahoma /west-central Arkansas
Monday afternoon. Warm front will begin to lift back north on Tuesday
with the potential for scattered showers/isolated thunderstorms along
and south of front in warm sector into the day Wednesday.
Still some significant differences in the operational models concerning
strong upper level storm system that will impact the region Thursday
into Friday. Generally trended toward the more compact and progressive
ECMWF solution that sweeps strong cold front through the area on Thursday.
With this scenario, overall winter weather potential would remain limited
as showers/thunderstorms move east before the colder air moves in behind
front.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 48 63 54 68 / 10 20 10 10
FSM 46 60 49 67 / 10 20 20 10
MLC 52 63 54 69 / 10 20 20 10
BVO 45 63 49 67 / 10 20 10 10
FYV 44 59 48 64 / 10 20 20 10
BYV 44 61 48 66 / 10 20 20 10
MKO 48 62 51 68 / 10 20 10 10
MIO 46 62 52 67 / 10 20 10 10
F10 49 63 52 69 / 10 20 10 10
HHW 52 61 51 69 / 10 20 20 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...None.
AR...None.
&&
$$
LONG TERM....30