Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/30/18
Area Forecast Discussion
National Weather Service La Crosse WI
718 PM CDT Mon Oct 29 2018
.UPDATE...
Issued at 716 PM CDT Mon Oct 29 2018
Band of light rain showers should continue to shift east and move
out of the area by mid-evening.
Some pretty big differences with the forecast tomorrow but maybe
it is just in the details. It looks cloudy with the front moving
through but it also appears the best forcing is to the south in a
narrow frontogenetic band /KMSN-KDBQ/ and south. 30.18Z NAM is
quite saturated in the lower levels for much of the forecast area,
while the RAP/HRRR model system is quite dry but for a brief 5k
ft cloudy period around mid-late morning. Otherwise, the RAP/HRRR
would suggest just mid-level clouds. Current forecast does have
the precipitation chances handled well in the afternoon /south of
the area/. Have shifted the slight chances a bit east during the
late morning. Lack of lower cloud in current observations to the
south /e.g., drier air mass than moist solutions believe/ and
forcing remaining south Tuesday should keep precipitation south.
00Z soundings will help diagnose air mass to our south and west
that is incoming for Tuesday.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 315 PM CDT Mon Oct 29 2018
Main forecast concerns are on rain chances on Tuesday.
Light sprinkles and a few rain showers noted over the forecast area
this afternoon as warm air advection moves through ahead of
approaching low pressure. Only expecting a trace to possibly a
hundredth of an inch of precipitation out of this activity as it
moves through. The low then pushes east out of eastern South Dakota
tonight as a trough approaches. The low washes out as the trough
approaches and pushes a weak cold front across the area during the
day on Tuesday. Mesoscale models are showing some very weak
reflectivity echo, mainly off the NAM solutions, but the HRRR
solutions are dry. Seeing disorganized frontogenesis on the NAM12
in the 900-600 mb layers, so cannot rule out a few light rain
showers or sprinkles mainly along and southeast of a Charles City
Iowa to Medford Wisconsin line Tuesday morning.
.LONG TERM...(Tuesday night through Monday)
Issued at 315 PM CDT Mon Oct 29 2018
The frontogenesis then ramps back up in the 700-600 mb layer Tuesday
evening, so we should see a band of light rain set up over
portions of northeast Iowa into far southwest Wisconsin. High
pressure then builds in Wednesday into Thursday with dry and quiet
weather expected. Flow aloft transitions to northwest Wednesday
night into Thursday with cooler temperatures expected. The next
chance for precipitation arrives Thursday night into Friday
morning as a shortwave tracks from the Dakota`s into the Mid
Mississippi River Valley. The bulk of the forcing for any
precipitation appears to say just to our southwest with this
system. A more organized potentially stronger storm system could
impact the region Saturday night into Sunday. Forecast models
continue to show differences during this timeframe so confidence
is low on timing and any potential precipitation amounts.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 716 PM CDT Mon Oct 29 2018
Most of the forecast should remain VFR. This evening there is
borderline LLWS values over the airfields.
The degree of low-level cloud on Tuesday is still somewhat
uncertain. It appears the best lift with a cold front moving
through will be found well south of the airfields and keep CIGS in
the VFR category. Plan on the wind shifting along the cold front
around mid-day Tuesday.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
UPDATE...Baumgardt
SHORT TERM...Wetenkamp
LONG TERM...Wetenkamp
AVIATION...Baumgardt
Area Forecast Discussion
National Weather Service Dodge City KS
627 PM CDT Mon Oct 29 2018
...UPDATE TO AVIATION...
.SHORT TERM...(This evening through Tuesday)
Issued at 314 PM CDT Mon Oct 29 2018
The water vapor loop and RAP analysis today revealed a fairly low
amplitude pattern across much of the CONUS, with a mean trough over
the Northern Rockies, ridging across the Upper Midwest, and another
trough across the Northeast. A strong northeast Pacific upper jet
was diving into Oregon and Washington. Satellite showed a lot of
high level cloud across the West and into the Central Plains. The
high cloud, along with lighter surface winds than originally
forecast, led to lower temperatures this afternoon. It still had yet
to reach 70 degrees as of 1945Z in Dodge City. Earlier in the shift,
today`s afternoon temperatures were lowered to account for these
short-term forecast changes.
The main challenge in the forecast for tonight into tomorrow will be
cold front timing and strength of winds behind it. As the Northern
Rockies trough moves out across the plains tonight, a cold front
will push south rather quickly. Much of southwest Kansas will see
frontal passage in the 09-12Z time frame, and there will likely be a
2-4 hour period of strong winds in the 25-35 mph range sustained.
Some gusts in the 40-45 mph range can be expected as well. As far as
temperatures go, we will definitely see a noticeable change, as
850mb temperatures will be dropping down into the +2 to +5C range.
Mechanical mixing due to the strong winds will be occurring, so
these 850mb temperatures should lead to afternoon surface
temperatures in the mid to upper 50s for most.
.LONG TERM...(Tuesday night through Monday)
Issued at 314 PM CDT Mon Oct 29 2018
The main interest in the Long Term will be right at the beginning of
the period Tuesday Night and Wednesday, as a fast-moving storm
system zips across the Central Rockies and across the Plains. There
is fairly good agreement among all of the models (high resolution
limited area and lower resolution global spectral) that
precipitation will develop first across the higher terrain of
Colorado and adjacent High Plains Tuesday evening. A fairly good
frontogenetic zone at 700mb will be across this region with a weak
wave along it, and this will be the driving force for upward
vertical motion and precipitation. The precipitation across
southeast Colorado will start as rain, then transition to a wet snow
Tuesday Night, and some of this wet snow is expected to mix with
rain as far east as a Lakin to Johnson to Elkhart line in the 09-15Z
Wednesday time frame.
As it appears now, the confidence in any accumulating snow is very
low, and it is probably more likely that these areas will still see
far more rain than snow and that it would only snow in heavier bands
of precipitation which would allow freezing level to drop to that
critical 1000-1200 ft AGL zone. The official forecast will reflect
up to one half inch of snow accumulation in northwestern Hamilton
County, but otherwise, no snow accumulation is forecast anywhere
else. As far as total precipitation amounts go, highest will be in
the southwest areas closer to Elkhart where up to three-tenths of an
inch may fall. Most other areas west of Highway 283 will see one to
two tenths and less than a tenth toward central and south central
Kansas.
Beyond Wednesday, we will see temperatures mainly in the 50s and 60s
for highs through the end of the week into the weekend as we see at
least a couple of reinforcing cold fronts (dry) as a northwest to
southeast jet stream configuration becomes a theme through the end
of the upcoming weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 623 PM CDT Mon Oct 29 2018
VFR conditions will prevail at all TAF sites through early Tuesday
afternoon. Southerly winds 5 to 10kt will persist across southwest
and central Kansas through late this evening as a developing
surface low remains anchored across eastern Colorado. A strong
cold front will then push southward across western Kansas later
overnight, generally after 07Z, turning winds northerly 25 to
35kt with localized gusts up to 40kt possible in the earliest
hours after the frontal passage. Northerly winds will then begin
to subside somewhat through Tuesday afternoon as the cold front
pushes further south through the Texas Panhandle and western
Oklahoma.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 46 58 39 55 / 0 0 70 40
GCK 45 56 37 54 / 0 0 80 40
EHA 46 57 35 50 / 0 0 90 70
LBL 46 58 38 52 / 0 0 80 60
HYS 46 57 40 56 / 0 0 40 10
P28 52 60 45 58 / 10 20 30 30
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Umscheid
LONG TERM...Umscheid
AVIATION...JJohnson
Area Forecast Discussion
National Weather Service Las Vegas NV
900 PM PDT Mon Oct 29 2018
.SYNOPSIS...One last quiet and mild day today before a cold front
passes through tomorrow which will bring breezy north winds and
cooler temperatures to the region for the mid week. No precip
expected however. Latter half of the week will begin a warming trend
to above normal temperatures by the weekend.
&&
.UPDATE...Area of high clouds ahead of approaching trough will
clear southern Nevada and northwest Arizona between 11 pm and 5 am
tonight. Cold front currently looks to be along a line from near
Pioche-Beatty-Independence CA. Have seen reports of peak winds
around 30 mph at Bishop and Tonopah so far. Hi-res models indicate
northwest winds will increase along the Highway 95 corridor between
Las Vegas and Indian Springs around midnight. Cold front looks to
arrive at McCarran International Airport around 4 am with higher
wind gusts to 30 mph throughout Tuesday. Likely see peak wind gusts
30-40 mph in the northwest valley. It will turn windy across the
Lake Mead National Recreation Area and lower Colorado River Valley
Tuesday as well. Still looks like winds will remain below lake wind
advisory criteria. Winds currently a little light in the Owens
Valley so have increased speeds tonight/Tuesday
&&
.SHORT TERM...
The focus of the short term was on the effects of a passing cold
front progged to pass through the region tomorrow morning and
shift winds to the north becoming breezy. There has been
consistent model to model and run to run agreement that this
passage will be dry and while hi-res solutions are suggesting some
very light radar returns possibly Tuesday, area soundings suggests
nothing should reach the ground from this elevated moisture. More
significant will be wind trends as the HRRR is suggesting 15-25
kt sustained north winds tomorrow afternoon (with gusts to 30+).
Latest NBM is also among the higher of the guidance available but
not quite as gung-ho as the HRRR at the moment. Went ahead and
trended towards the NBM for now to boost wind potential beginning
after 12Z tomorrow. Do not believe it will warrant Lake Wind
Advisory criteria at the moment but this will need to be monitored
closely with later runs. Winds will subside overnight Tuesday but
breezy conditions could again be possible Wednesday.
Also of note will be the 10+ degree cooler afternoon highs
tomorrow and Wednesday. Looking at the last few 10+ degree cold
front passages, the best performing guidance have surprisingly
been bias corrected variations of the CONSall and CONSraw. Thus,
have opted once again for these values for the Max Ts tomorrow and
Wednesday.
.LONG TERM...
Ridge of high pressure off the Pacific coast will keep conditions
dry and mild through the extended period. Temperatures will average
several degrees above normal through the period. Given the
northwesterly flow aloft, we will need to watch for occasional weak
disturbances sliding through the Great Basin, which could result in
brief cool downs and enhanced north winds, but overall conditions
look quite tranquil through early next week.
&&
.AVIATION...For McCarran...Light, northeast winds will continue for
the remainder of the afternoon before shifting to the southwest this
evening with speeds around 8 knots. Late tonight a cold front will
approach and pass through the valley causing the winds to shift to
the northwest between 08z-11z and increase to 9-12 knots. North
northwest winds will continue to increase throughout the morning,
peaking between 16z-23z with speeds of 15-20 knots gusting 25-30
knots. Speeds will come down tomorrow evening after 03z closer to 10
knots overnight.
For the rest of southern Nevada, northwest Arizona and southeast
California...This afternoon, gusty south to southwest winds will be
likely across the western Mojave Desert and Mohave County through
this evening with speeds around 15 knots gusting 25 knots. A cold
front will push southward from central NV across the southern Great
Basin and Inyo County this evening, reaching the Interstate 15
corridor during the early morning hours Tuesday and exiting to the
south of Lake Havasu City by late Tuesday morning. Gusty, north
winds will follow with speeds generally between 15-25 knots gusting
25-35 knots. Decreasing clouds can be expected overnight.
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
UPDATE...Pierce
AVIATION...Guillet
SHORT TERM/SYNOPSIS...TB3
LONG TERM....Outler
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