Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/15/17
Area Forecast Discussion
National Weather Service La Crosse WI
545 PM CST Tue Nov 14 2017
.SHORT TERM...(Tonight and Wednesday)
Issued at 300 PM CST Tue Nov 14 2017
Messy forecast for this evening, but luckily temperatures are all
above freezing so any precipitation should remain liquid. Main
challenge for this evening will be dense fog potential, especially
west of Mississippi River.
Approaching mid level trough continues to hold area in warm air
advection regime, with hints of a warm front laid up across
northeast Iowa as of 19z. Along and ahead of this front visibilities
have been limited, especially across parts of northeast Iowa into
southern Minnesota as higher dew points trying to advect in.
While visibilities have fluctuated somewhat, and vary from area to
area, short term guidance, including latest HRRR surface visibility
fields, suggest parts of southeast Minnesota and northeast Iowa
could actually worsen before improving this evening. Some of this
depends on where precipitation increases at as wave approaches. If
bulk of that stays north and east of fog area, see no reason why fog
would magically improve. Will include an advisory for the evening
hours and perhaps later shifts can adjust as needed.
Meanwhile, short term guidance consistent with idea of light
precipitation this evening, but varies in exact area coverage.
Probably a mix of drizzle or rain, with better chance for just rain
further east.
As main wave slides through early Wednesday, precipitation chances
will end from west to east, even as colder air begins to filter in.
Secondary short wave dropping through western Great Lakes, could
also generate a little additional light precipitation /mix of rain
and snow/ along and north of Interstate 94.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 300 PM CST Tue Nov 14 2017
Quiet weather settles in for a bit mid week, with ridge passage
Wednesday night. If winds settle for a bit and skies clear at all,
could see low temperatures bottom out in bog areas of central
Wisconsin so lowered them a bit.
Otherwise attention turns to next wave late in the week, with
initial warm air advection possible already Thursday night. Not
expecting any significant impact with precipitation but warmer air
Friday should transition any threat over to mainly rain. Have
continued to trend rain threats higher as energy phases with trough
passage by Friday night.
Colder air returns on Saturday so exiting precipitation could
briefly switch over to light snow or flurries before ending, with
blustery, northwest winds setting the stage for a chilly weekend.
Lots of variability in medium range guidance for next week.
Models have been hinting at more of a blocking, high amplitude
pattern setting up which could mean extended cool and dry period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 545 PM CST Tue Nov 14 2017
Widespread IFR conditions across the region early this evening
and little change is expected through the night. Prevailing
visibilities of less than a mile are common across southeast
Minnesota and these should have some slow improvement through the
evening. As an area of low pressure over eastern South Dakota
moves east, light rain is expected to develop which should help to
start cleaning up the visibilities. However, confidence is not
high in this scenario, especially if light drizzle forms instead
of rain, this could actually promote keeping the visibility down.
The light rain and drizzle will end overnight as the surface low
and cold front move through allowing for some improvement in both
the visibility and ceiling, but IFR conditions should still
prevail until mid to late morning. Will continue to show VFR
conditions developing as the low clouds scatter out but this is a
very low confidence forecast. Forecast soundings from the 14.18Z
NAM indicate the low level moisture gets trapped underneath the
inversion and in the cyclonic flow behind the surface low, the
MVFR ceilings could persist for much of the day.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...Dense Fog Advisory until midnight CST tonight for MNZ086-087-
094>096.
IA...Dense Fog Advisory until midnight CST tonight for IAZ008>011-018-
019-029-030.
&&
$$
SHORT TERM...Shea
LONG TERM...Shea
AVIATION...04
Area Forecast Discussion
National Weather Service Dodge City KS
653 PM CST Tue Nov 14 2017
...updated aviation section...
.SHORT TERM...(This evening through Wednesday)
Issued at 321 PM CST Tue Nov 14 2017
Afternoon water vapor loop and RAP analysis revealed a strong, zonal
Pacific jet from Northern California to the Dakotas. A shortwave
trough was embedded within this jet core across Wyoming. This
induced fairly strong low level response on the High Plains, and was
largely responsible for allowing low stratus to erode quicker and
farther east than most morning mesoscale model solutions were
suggesting. This resulted in temperatures warming well into the
upper 60s to lower 70s for a larger portion of southwest and west
central Kansas.
The shortwave trough in Wyoming will continue to push east tonight,
pushing a cold front at the surface south across western Nebraska
and eventually western Kansas later tonight. Whatever low stratus
attempts to make it back west this evening will quickly become
shunted quickly south and east once the front moves through.
Dewpoints will fall to around 30F by daybreak, but there will not be
much in the way of cold air behind this front, given the degree of
downslope trajectory of the parcels in the low levels. The coldest
air, by far, will be well off to the northeast toward the Upper
Midwest region. Winds behind the front will be around 15 to 20 mph
for a 3 to 5 hour period early in the morning before weakening to 10
mph or less by afternoon. It should turn out to be rather pleasant
Wednesday afternoon with a lot of sunshine, very little wind, and
temperatures topping out 57 to 60F for a high.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 321 PM CST Tue Nov 14 2017
A much more intense Pacific jet will be entering the Rockies and
adjacent Central Plains Friday/Friday Night, but again this will
also be low amplitude with the core of the jet passing just north of
our southwest Kansas region. The end result will be a surface low
tracking from east-central Colorado through Central Kansas before
shooting off into Illinois. Light accumulating precipitation will be
confined to areas of southern Nebraska and perhaps far northern
Kansas, but west central and southwest Kansas are expected to remain
dry. Thursday will be quite mild, but breezy, ahead of the
approaching storm. Highs in the upper 60s west to upper 50s east.
Friday will be more interesting, as the surface low really begins to
deepen just to our northwest. A surge of strong west-southwesterly
downslope momentum will allow 850mb temps to rocket up to around
+21C at Dodge City. 850mb temp of +21C at Dodge City mixes down to
around 82F at the surface, and this would be a record high for the
date (November 17th record is only 80F at Dodge City). There will
likely be an abundance of high cirriform cloud cover, although the
opacity of this cloud is nearly impossible to forecast at this
stage. We will be going with highs in the upper 70s with around 80F
along the Oklahoma border. This is a +2F adjustment of the
SuperBlend starting point guidance. At any rate, it definitely looks
quite warm Friday. Strongest winds will likely be south of the
Arkansas River where gradient will be stronger. winds along the
Oklahoma border could be quite strong in the 20-30 mph range (if not
a touch higher).
As has been the theme with all these waves passing by, the coldest
air will be well off to our northeast given downslope momentum
behind the front masking a lot of the cold advection. After this
storm system moves through, we will return to above normal
temperatures going into the end of this forecast period (beginning
of next week). A major shift in the large scale circulation regime
does not seem all that likely through next week, so the prevailing
below normal precip and near/above normal temperatures should
continue until such hemispheric pattern shift occurs.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 549 PM CST Tue Nov 14 2017
A cold front will move through the area between about 4 and 8 UTC.
The HRRR, with modest support from other models, does show some
westward post frontal redevelopment of IFR level stratus across
central Kansas; more likely to briefly impact the HYS terminal than
than DDC. Farther west, at GCK/LBL - no ceilings are be possible.
The winds should pick up overnight behind the front, but
generally renain below 20 knots.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 40 59 34 62 / 0 0 0 0
GCK 38 57 35 65 / 0 0 0 0
EHA 39 56 37 70 / 0 0 0 0
LBL 40 59 34 68 / 0 0 0 0
HYS 39 58 33 60 / 0 0 0 0
P28 45 61 35 59 / 10 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Umscheid
LONG TERM...Umscheid
AVIATION...Russell
Area Forecast Discussion
National Weather Service Houston/Galveston TX
912 PM CST Tue Nov 14 2017
.SHORT TERM [Thursday Through Friday Night]...
Surface analysis shows low pressure over the Texas Panhandle at
03Z. With still a bit of a ridge axis over SE Texas, winds are
light from the SE. Dewpoints are in the low 60s so quite possible
to get some fog across the area especially west and northwest of
Houston. Overall the forecast looks on track and the only changes
made to the forecast grids were to keep up with ongoing trends.
Overpeck
&&
.PREV DISCUSSION /Issued 538 PM CST Tue Nov 14 2017/...
A large region of surface high pressure located just west of the
Ohio Valley is helping to keep our winds out of the southeast this
afternoon. Observations show dew points currently in the upper
50s to low 60s, and with the 850 mb ridge situated over SE TX,
conditions should remain dry overnight with precipitable water
values lowering overnight to around one inch.
The chance for patchy fog remains in the forecast late Tuesday night
into early Wednesday morning. The NAM forecast soundings builds in
two broken to overcast cloud decks, one at 925 mb as well as one
around 800 mb. On the contrary, GFS forecast soundings are trending
more dry in the mid levels but still building in the same low level
stratus around 925 mb, early Wednesday morning. This layer of
stratus could influence our fog development across the region, as
moisture below this stratus deck, along with calmer winds could aid
in patchy fog and misty conditions at the surface. SREF guidance
shows patchy fog moving in from the northwestern around 06Z, with
coverage spreading southeastward through the early morning hours.
The HRRR short term guidance also favors coverage in the
northwestern portion of the CWA overnight, with patchy fog rising
and clearing out around 15Z. Low temperatures tonight should dip
into the low 60s to the north and low 70s along the coast.
For Wednesday, short term guidance keeps the morning and early
afternoon hours on the dry side, while well north of our area
short term guidance shows a weak frontal boundary (prior to the
front that is expected to reach SE TX Saturday) moving through
Wichita Falls and into the Dallas/Fort Worth area. Because of the
shallow nature of this feature, this boundary should modify
quickly as the system moves southeastward. Therefore, current
model runs do not indicate this weak front making it into our
northern zones, but instead shifts the boundary and most of the
energy more eastward into Oklahoma and Arkansas. Regardless, this
feature could still help to provide lift resulting in some
showers in the northern half of our CWA. This slight chance for
showers will hold through the early afternoon Thursday. Otherwise,
the remainder of the day Thursday into Friday will be on the dry
side as heights rise associated with a surface ridge building in
over the northeastern Gulf of Mexico. High temperatures Thursday
and Friday will be in the upper 70s to low 80s, with Friday being
the warmer day.
The next best chance for precip arrives early Saturday, as a cold
front approaches the region. Global models such as the GFS and
ECMWF are still in disagreement over the timing and strength of
this front. The GFS remains the earlier of the two, moving the
front into the northern zones of the CWA as early as 12Z Saturday,
with most of the precip clearing the coast by 06Z Sunday. The
ECMWF on the other hand appears to be a little drier than the GFS,
bringing precip into the northern zones Saturday 12Z but lingers
a little longer eventually clearing the coast around 12Z Sunday.
Currently, trending towards the earlier solution with most of the
precip moving offshore late Saturday.
Behind the front, high pressure will build back into the area,
keeping us dry until next Tuesday. Sunday night into the Monday will
be the coolest night, with low temperatures falling into the low 40s
in our northern most counties to upper 50s along the coast.
Temperatures will attempt to rebound Sunday, as high temperatures
struggle to reach back into the low 70s. High temperatures Monday
through Wednesday should remain in the low to mid 70s.
Hathaway
.AVIATION...
Not much change in thinking from the previous TAF set on fog
potential - IFR may be possible at foggy spots CXO and LBX, and
keep the MVFR TEMPO at CLL per HRRR runs. Elsewhere, MIFG at most
seems appropriate. Most significant change is to remove the
category degradations in ceiling. While the NAM keeps enough low
moisture to allow for this, it is largely an outlier, and
satellite observations suggest this may not occur. Keep FEW/SCT
references as some deference and to make for easier amending if
needed. Do suspect this will allow for greater radiational
cooling overnight and tends to increase confidence in the
inherited visibilities.
Luchs/22
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 63 79 64 80 66 / 10 10 20 20 10
Houston (IAH) 61 80 65 79 68 / 10 10 10 20 10
Galveston (GLS) 68 77 70 77 71 / 10 10 10 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
NEAR TERM...39
SHORT TERM...Overpeck
Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
601 PM CST Tue Nov 14 2017
.SHORT TERM...(This evening through Wednesday)
Issued at 330 PM CST Tue Nov 14 2017
The main weather focus over through Wednesday afternoon is the
passage of a surface cold front and mid-level shortwave. As of 21z,
the front was entering far NW Neb near CDR and GRN. A pre-frontal
trough crossed the forecast area this afternoon, clearing out the
stratus. Despite strong lift and forcing this evening, precipitation
is not a concern as moisture is lacking overall. Surface dew point
depressions are 30F+ and H5-7 RH is generally less than 70% per RAP
mesoanalysis and forecast soundings. However, low level saturation
lies just east of the area as seen by a very slowly eroding stratus
deck from MCK to LXN to OFK. Can`t rule out a brief period of patchy
fog in eastern Frontier and Custer counties late this evening before
the fropa. Increased winds along and behind the front as the general
model consensus shows 35+ kt flow at H85, 1.5 PVU sfc reaching
450mb, and sfc pressure changes of 1-2 mb/hr. Therefore, kept
tonight`s lows on the high end of guidance despite clear skies and
strong CAA. H85 temps barely surpass 0C tomorrow and with low level
flow relaxing under a sfc high and mid-level ridge. Made little
change to highs in the lower 50s, which coincides with the cooler
end of guidance (ECS). However, return flow late in the day may help
push temps warmer than forecast in the panhandle.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 330 PM CST Tue Nov 14 2017
Rain and snow chances during the next 7 days revolve around a single
event Friday evening. A positively tilted trof moves through with
modest 1030 mb Pacific high pressure to follow Saturday and Sunday.
The forecast leans on the wetter model, the ECM, which shows
stronger midlevel frontogenesis and produces around a tenth of an
inch of liquid. Its rain changing to snow Friday evening as h700mb
temperatures fall into the single digits below zero.
Otherwise the models are in reasonably good agreement with warming
conditions Thursday and Friday. The ECM will back an arctic cold
front into ncntl Neb Tuesday next week. The pattern is progressive
with weather systems in motion. The SREF indicates a fog
free/stratus free forecast through Saturday and the GFS/ECM would
suggest the same ahead of the arctic front next week. The moisture
return in both cases appears to be directed toward the midwest.
The temperature forecast is a model blend plus the previous forecast
plus bias correction. Bias correction had little impact on the
forecast and tended to increase highs a degree or two and lower
minimum temperatures the same. This suggests a predictable pattern
of warming highs into the 50s and 60s Thursday and Friday followed
by a cool down into the 40s Saturday. A warming trend develops
Sunday and Monday. There was no model consensus with the arctic
front next Tuesday. The faster ECM was colder with highs in the 30s
and 40s while the slower GFS kept the high farther north and
featured highs in the 50s and 60s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 555 PM CST Tue Nov 14 2017
Stratus over eastern Nebraska. Across western Nebraska and the
Sandhills a cold front will move across bringing high clouds into
the area but no precipitation will be associated with the front.
Winds will be the main concern this forecast period with gusty
northwest winds 10 to 15 mph, and gust up to 25 mph overnight,
mainly across the northern Sandhills.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...Snively
LONG TERM...CDC
AVIATION...Gomez