Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/14/23
Area Forecast Discussion...Updated
National Weather Service Billings MT
805 PM MDT Fri Oct 13 2023
.UPDATE...
Weak upper low was shifting out of southeast Montana this
evening. Observations and radar imagery were indicating just cloud
cover was left with this wave, as earlier weak showers have died
off. Not expecting much more activity, as weak upslope flow was
becoming much weaker and the wave exits the area, so pulled
remaining PoPs. Low levels remain adequately moist for potential
fog formation tonight, although need to have clouds break up some
for the fog to form. Temperature/dewpoint spreads were still on
the order of 6-8 degrees, so need to cool things down (which will
be caused by clouds decreasing). HRRR was not as robust in the fog
forecast tonight (compared to last night), so patchy fog in the
forecast for most places should be adequate. Will be a chilly
night as lows fall to around freezing for mainly places. If the
cloud cover holds on more than expected, lows will end up a bit
warmer. TWH
&&
.DISCUSSION...
Tonight through Sunday night...
Vorticity was moving through SE MT this afternoon per water vapor
imagery and mesoanalysis. Moist easterly upslope flow continued
over the area and some echoes have popped up in W Big Horn County.
Updated afternoon PoPs again to reflect the areas of rain in
Sheridan County and echoes in Big Horn County. A few snowflakes
mixed in earlier with the rain on the webcam at the
Sheridan/Johnson County line. Went with 60% PoPs on the county
line based on cams. Otherwise had 20 PoPs over much of the rest of
the area due to the upslope flow and vorticity over the E.
For tonight, kept 20 PoPs over areas E, W and S of KBIL during the
evening as the vorticity exits the area. Easterly flow continues
through the night and HRRR indicated patchy fog forming over the
area so added that to the grids. Skies will become partly cloudy
and temps will be in the upper 20s/lower 30s allowing the
formation of some frost. Weakly diffluent flow aloft will be over
the region on Saturday with vorticity approaching the SW mountains
in the afternoon. Added 20 PoPs to the western mountains for the
afternoon and evening. Otherwise, it will be warmer with temps in
the 50s to lower 60s. Upper ridging builds over the area for the
rest of the period with dry weather and temps mainly in the 60s on
Sunday. Arthur
Monday through Friday...
For the long term, ridging continues to build over the region
with westerly/northwesterly flow to start the week. Warm and dry
conditions will be felt to start the week, with highs in the
60s/low 70s and minimum RH values between 30-40% on Monday and
Tuesday.
The ridging will begin to break down on Tuesday, as a shortwave
pushes into northern Montana. An increase in precip chances will
accompany this shortwave, with PWAT values in the range of
.4-.75. With the shortwave moving quickly, the chances for notable
rainfall totals is very low. NBM guidance shows most of the CWA
reaching a 10-30% chance of 0.25 inches of QPF. Overall chances
for precip are 30-60%, with the higher chances being in the
south-central part of the CWA, as well as the mountains.
As the shortwave departs on Wednesday, southerly flow will
dominate as another ridge builds over the Western US. Cooler high
temps, in the 50s/low 60s, for Wednesday, before a return to
highs in the upper 60s/ low 70s to end the week.
Matos
&&
.AVIATION...
VFR will prevail tonight for most of the area. There will be
patchy fog tonight into Saturday morning, producing MVFR or lower
conditions. The areas most likely to receive fog or low stratus
and IFR/LIFR are the foothills west of KBIL, including the KLVM
area. Expect areas of mountain obscuration into Saturday.
Arthur/RMS
&&
.PRELIMINARY POINT TEMP/POPS...
Sat Sun Mon Tue Wed Thu Fri
-----------------------------------------------------------
BIL 033/058 041/068 044/072 051/070 045/060 040/064 043/071
00/B 00/B 00/B 03/W 42/W 10/U 00/U
LVM 032/062 038/068 040/073 046/066 036/059 035/067 040/074
01/B 10/B 00/B 15/W 31/B 00/U 00/U
HDN 030/060 036/067 038/073 044/071 041/060 036/064 036/072
00/B 00/B 00/B 03/W 52/W 10/U 00/U
MLS 032/055 034/062 039/069 045/069 045/057 037/059 038/069
00/U 00/B 00/B 01/B 42/W 10/U 00/U
4BQ 030/055 033/064 040/071 045/071 044/056 038/059 038/070
00/U 00/B 00/U 01/B 42/W 10/U 00/U
BHK 030/051 029/059 036/069 043/068 041/055 035/056 033/066
00/B 00/B 00/U 01/B 32/W 10/B 00/U
SHR 025/057 033/065 037/071 044/071 038/055 034/061 036/071
00/B 00/B 00/B 02/W 62/W 10/U 00/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
805 PM CDT Fri Oct 13 2023
...New UPDATE...
.UPDATE...
Issued at 805 PM CDT Fri Oct 13 2023
The cold front has reached a Del Rio to San Antonio line. Isolated
showers and thunderstorms have developed over San Antonio, in line
with recent HRRR runs. We have updated to include a slight chance of
isolated showers and storms near and south of the front farther east
into Bexar and Atascosa counties.
&&
.SHORT TERM...
(Tonight through Saturday night)
Issued at 204 PM CDT Fri Oct 13 2023
Around the noon hour, the cold front entered the Hill Country and
has continued to make steady progress southward. Out ahead of this
front, conditions remain warm and humid where the afternoon highs
reach into the low 90s for many. Pesky morning and early afternoon
cloud cover gradually decreases through the afternoon but a line of
cumulus will continue along the immediate frontal boundary. In the
wake of the front, a drier and cooler airmass will filer southward
into the region with the northerly flow and as surface high pressure
builds in. Skies should clear out across our northern and eastern
zones but pesky moisture around the 850 to 700 mb layer allows for
lingering cloud cover across our southern and western zones from
this evening into midday Saturday. Additionally, enough lift along
with deep enough moisture may result in some isolated to widely
scattered shower activity and perhaps a storm or two tonight over
the Rio Grande Plains. With the Annular Eclipse Saturday, the most
optical viewing conditions remains forecast across the northern and
eastern portions of the Path of Annularity compared to the western
portions where clouds will be most likely to obscure the viewing
conditions. The lingering sky cover to the west could continue into
Saturday night before eventually clearing out into Sunday.
Temperatures for tonight should range from the low 50s in the Hill
Country under mostly clear skies to the mid to upper 60s across our
southern and western zones where cloud cover is most abundant. The
highs on Saturday will trend cooler ranging from the mid 70s into
the low to mid 80s. Saturday night will see overnight lows dip into
the 50s for many while locations along the Rio Grande holds around
the 60 degree mark.
&&
.LONG TERM...
(Sunday through Friday)
Issued at 204 PM CDT Fri Oct 13 2023
The upper level flow will become northwesterly Sunday with a deep
trough over the eastern part of the country and high amplitude ridge
over the west. High pressure at the surface will move across from
west to east keeping dry weather over our CWA. Temperatures for the
first few days of the week will remain below normal. Highs Sunday
through Tuesday will be mostly in the 70s and lows will be in the 40s
and 50s. Wednesday the surface high will be to our east and winds
will turn to the southeast. This will bring warmer, moister air back
to the region. Temperatures will climb back up to near normal
Wednesday and stay there for the rest of the week. Thursday and
Friday a cold front will move into the region bringing a chance for
showers and thunderstorms.
&&
.AVIATION...
(00Z TAFS)
Issued at 620 PM CDT Fri Oct 13 2023
The cold front continues to progress south, and as of 23Z was located
just north of a DRT-SAT-3T5 line. There is a low chance of isolated
SHRAs to form south of this line over the next couple of hours along
the front. Otherwise, VFR post-frontal conditions, with a BKN 5-7K
foot stratus deck possible overnight and into the morning hours near
and southwest of a DRT-HDO-PEZ line. Winds becoming N to NNE behind
the front, with some gusts later tonight along the I-35 corridor to
around 20KT, and gusts mixing out more areawide to around 20-25KT
between 14Z-18Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 58 80 54 76 / 0 0 0 0
Austin Bergstrom Intl Airport 57 80 51 77 / 0 0 0 0
New Braunfels Muni Airport 61 81 53 80 / 0 0 0 0
Burnet Muni Airport 53 78 50 74 / 0 0 0 0
Del Rio Intl Airport 66 82 60 84 / 10 10 0 0
Georgetown Muni Airport 55 78 51 75 / 0 0 0 0
Hondo Muni Airport 63 82 55 80 / 10 0 0 0
San Marcos Muni Airport 58 81 52 77 / 0 0 0 0
La Grange - Fayette Regional 60 79 53 75 / 0 0 0 0
San Antonio Intl Airport 62 82 55 79 / 10 0 0 0
Stinson Muni Airport 65 82 57 80 / 10 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Short-Term...Brady
Long-Term...18
Aviation...76
Area Forecast Discussion
National Weather Service Grand Rapids MI
937 PM EDT Fri Oct 13 2023
LATEST UPDATE...
Update/Marine
.UPDATE...
Issued at 937 PM EDT Fri Oct 13 2023
A lull in the rain has moved in for portions of southwest MI. This
is due to some of the synoptic lift weakening for the time being.
As we head overnight showers should fill back in, especially over
the I-96 corridor and southward, with the low over northwestern
IL shifting eastward. 850mb to 700mb frontogenesis is expected to
increase overnight with the low passing to the south providing a
more focused area of rain. As the low continues its eastward
track precipitation will gradually taper off from northwest to
southeast Saturday afternoon into Saturday evening. Currently 1 to
2 inches has fallen along and north of a Holland to Mount
Pleasant line with more of a tenth to half an inch south of that
line. An additional 0.5 to 1.5 inches of rain is possible now
through Saturday afternoon.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 250 PM EDT Fri Oct 13 2023
- Rainy night ahead
Upper level PV anomaly in Iowa takes a track into northern
Indiana later tonight. With the CWA being on the north side of
this feature the main mid level dry slot should stay south of the
area. We have already had some stronger bands of precipitation
mainly north of Grand Rapids where better FGEN in the DGZ existed.
Some places saw over an inch of rain. Looking at the rest of the
night the FGEN persists as the moisture remains deep most of the
night. This will support continued rain, some of which could be
heavy. It`s not until Saturday afternoon that the deeper moisture
shifts south of the CWA. As a result we will maintain the high
POPs. Overall the MU CAPE values have trended down but thus far it
has not taken much to generate storms. Most models keep the CAPE
just south of the CWA but the NAM and RAP bring some into our
southwest CWA which is where we will feature the a risk for
thunder. If we combine what rain has fallen with the projected
amounts for tonight into Saturday, much of the area should end up
with storm total values of 1-2 inches with locally higher swaths.
Rivers will be on the rise but the most likely scenario keeps the
risk for impacts low. Urban and poor drainage flooding is a
possibility.
- Cool through Saturday night
Ensemble trends keep the max temperatures in 50 to 55 degree range
for Saturday which is well below normal. Northerly flow behind the
departing storm will draw down cooler air from Ontario. Overnight
lows will end up in the 40s for tonight and Saturday night.
Partial clearing Saturday night may support values dropping into
the 30s.
.LONG TERM...(Sunday through Friday)
Issued at 250 PM EDT Fri Oct 13 2023
-Lake Effect Showers Sunday into Monday-
As the low pressure system bringing rainfall to lower Michigan in
the short term exits, most will stay dry Sunday into Monday, however
cloudiness and cool temperatures persist thanks to upper-troughing
remaining overhead and northerly flow, keeping highs in the fifties.
As 850 mb temps fall to near zero, this will generate enough lake
induced instability for scattered lake effect showers. However,
northerly to slightly northeasterly flow will keep them limited to
near the shoreline and over the lake. However, Sunday night and
Monday the Lansing and Jackson areas could be clipped by lake effect
showers off of Lake Huron as a shortwave rounds the parent upper
trough through lower Michigan.
-Frost Possible Mid-Week-
Some clearing is possible Tuesday and Wednesday as surface and upper-
level ridging traverses the area. In areas where more notable
clearing takes place frost, and even freezing temperatures near
US10, is possible Monday Night and Tuesday Night.
-Chance of Rain Late Week, Warming to Near Normal-
Our next chance of rain is possible late next week as an upper-level
trough passes through the area. WPC cluster analysis shows notable
uncertainty as to the timing and positioning of this trough
resulting in stark differences in model spread for timing of
precipitation. The GFS sends the initial shortwave north of the area
Thursday as a trough over the central plains digs in resulting in
ridging and dry conditions until Friday when the main trough moves
through. The ECMWF ands to some extent the GEM solutions bring
troughing rainfall into the area Thursday. Cluster analysis shows
the GEFS ensemble locked into the GFS solution, with phase spaces
showing similar for the GEM to an extent.
Am feeling the GEFS is underdispersive as a result of clustering
alone so early, however there is notable uncertainty with the timing
of any precipitation. This is reflected in the ongoing forecast with
bimodal precipitation maxes of chance pops Thursday and Friday due
to the differing solution sets and their influence in the NBM.
However, there is lower variance between ensembles on temperatures
as a result of this with late week high temperatures climbing to
near to slightly above normal.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 630 PM EDT Fri Oct 13 2023
A mix of VFR/MVFR conditions early this evening will gradually
deteriorate to a mix of IFR/MVFR late this evening and overnight
into Saturday morning due to lowering cigs/visbys and areas of
rain.
An isolated thunderstorm cannot be ruled out early Saturday
morning mainly at our southern terminals. However there is not
enough potential for a thunderstorm to warrant inclusion in any of
the terminal forecasts at this time.
Easterly winds will remain brisk and gust to around 25 to near 30
kts at times overnight and Saturday. The mix of mainly IFR/MVFR
conditions will continue through early Saturday evening.
&&
.MARINE...
Issued at 937 PM EDT Fri Oct 13 2023
As low pressure over northwestern IL shifts east overnight the
pressure gradient will tighten bringing the potential for gales
overnight into Saturday, the best chance for gale force gusts will
be toward the open waters with gusts around 30 more likely closer
to the shoreline. Easterly winds become more northeasterly
Saturday with gales remaining possible through the day south of
Whitehall. Small Craft Advisory conditions could linger through
Sunday with lighter winds returning for next week.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...Gale Warning until 8 PM EDT Saturday for LMZ844>847.
Small Craft Advisory until 8 PM EDT Saturday for LMZ848-849.
&&
$$
UPDATE...RAH
SHORT TERM...MJS
LONG TERM...Thomas
AVIATION...Laurens
MARINE...RAH
Area Forecast Discussion
National Weather Service Morristown TN
1023 PM EDT Fri Oct 13 2023
...New UPDATE...
.UPDATE...
Issued at 1003 PM EDT Fri Oct 13 2023
Seeing some brief spotty showers pop up and dissipate across the
valley, concentrated near and north of Knoxville recently. HRRR
has these showers on and off primarily in the central and northern
portions of the TN valley through the overnight hours. Otherwise
brought some RAP in for temperatures which have been on the warm
side this evening. Remainder of the forecast is on track.
&&
.SHORT TERM...
(This evening through Saturday)
Issued at 309 PM EDT Fri Oct 13 2023
Key Messages:
1. Sprinkles and/or light rain showers tonight and mainly Saturday
morning. Rainfall amounts will be light.
2. Breezy conditions expected for Saturday afternoon.
Discussion:
Currently, Increasing boundary layer moisture and isentropic lift
is pulling clouds and some very light rain/sprinkles across much
of east Tennessee and southwest North Carolina along and south of
interstate 40. This is in response to pressure falls across the
mid-west as a system moves toward the Ohio valley.
The boundary layer jet will continue to produce a good deal of
cloud cover overnight with some sprinkles and light showers.
Moisture layer is rather shallow with PWs quite low. Any rainfall
will be quite limited and less than 0.05 inch with much of the
area remaining dry.
The cloud cover and southerly flow will produce a mild night with
temperatures in the 50s to lower 60s.
For Saturday, the low-level southerly jet will continue to produce
sprinkles and light showers across southwest Virginia and
northeast Tennessee in the morning. For the afternoon, the
moisture plume will move east of the area allowing the sunshine to
return from west to east across the region. The return of sunshine
will allow for better mixing with gusty winds/breezy conditions
over much of the area.
The pre-frontal boundary will move across the region in the
afternoon with some light showers possible but again most areas
remaining dry. Again, HREF shows limited QPF with this boundary.
&&
.LONG TERM...
(Saturday night through next Friday)
Issued at 309 PM EDT Fri Oct 13 2023
.LONG TERM...
(Saturday night through Friday)...
Key Messages:
1. Turning much colder Saturday night through Tuesday.
2. There will be showers around through Monday, but rainfall amounts
will be light.
3. Dry and warmer mid week with another chance of rain Friday.
Discussion:
Behind Saturdays cold front as we start the extended forecast, much
of the moisture will shift eastward. However upper trough following
the front will bring in some much colder air Saturday night through
Monday. The upper trough will deepen during this time and shortwave
energy rotating through the trough from the northwest will keep
temperatures much colder than this weeks mild temperatures. The low
level northwest flow will develop showers across the region with
highest chances in the north and the eastern Tennessee mountains.
The showers will be light but it will be cold enough for some very
light snow showers at the highest elevations. No significant
accumulations expected. Temperatures over the highest elevations
will likely dip near to around freezing Sunday night and Monday
night at elevations above 5000 feet.
The cloud cover with the wrap around moisture after the main low
moves off the coast Sunday will also help to keep temperatures cold.
The low is expected to deepen and a new upper low may form in the
deep trough or just have the trough become very elongated over the
eastern Tennessee Valley and southern Appalachians and continue to
bring showers across the region through Monday. Monday night the
trough finally begins to shift eastward and this will bring an end
to the showery pattern Tuesday morning. Tuesday surface high
pressure moves in and ridging in the upper levels approaches from
the west. This will bring a warming trend with dry conditions
through Thursday. A new frontal system moves into the Plains
Thursday and then will move into the forecast area Friday. There
will be a good chance of showers with this system Friday. This
system is expected to move through slower and may help with the
current drought across the area.
&&
.AVIATION...
(00Z TAFS)
Issued at 742 PM EDT Fri Oct 13 2023
Ceilings will gradually deteriorate overnight to MVFR area wide by
8z under light winds. Additional light scattered rain showers are
possible tomorrow. MVFR to near IFR ceilings will improve to VFR from
west to east after front passes through by 17z for all TAF sites.
Post frontal passage, winds will switch to westerly and increase
markedly, with 20 knot gusts likely in the afternoon hours through
the end of the period.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 61 75 54 60 / 10 10 10 20
Knoxville McGhee Tyson Airport, TN 61 74 53 57 / 40 20 20 30
Oak Ridge, TN 60 72 51 58 / 30 20 20 40
Tri Cities Airport, TN 58 70 50 55 / 50 30 60 40
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
SHORT TERM...Wellington
LONG TERM....TD
AVIATION...Wellington
Annular Eclipse Sky Cover Forecast Discussion (Saturday Morning).
Latest ensemble guidance and short- range model runs indicate
pre-frontal clouds will bring mostly cloudy skies to the area by
Saturday morning. The HREF shows high level clouds entering the
area after 8:00 am (peak eclipse will happen around 9:20 am for
our area). Right now, the EC Ensemble highlights a 60-100% chance
of cloud cover greater than or equal to 75% along the I-5 corridor
and north of I-80. Depending on the exact timing and speed of the
front, a few breaks in cloud cover may be possible south of I-80.
Possible trace amounts of rainfall may accompany these clouds.
//Forrest
&&
.EXTENDED DISCUSSION (Tuesday THROUGH Friday)...
Latest cluster analysis indicates that the mid to late week
period looks to be dominated by anomalous ridging aloft. As a
result, quiet weather looks to prevail throughout the long term
period. Temperatures will also look to rapidly warm to above
normal values during this time frame. Probabilities of exceeding
90F are only in the 20-40% range for portions of the northern
Sacramento Valley, but probabilities of exceeding 85F are still in
the 40-70% range throughout much of the Valley. While not a
robust heat event, mid- October normal high temperatures are
generally in the upper 70s to low 80s for Valley locations.
&&
.AVIATION...
Despite incoming cloud cover, generally VFR conditions prevail at
TAF sites through the forecast period. Slight (10-15%) chance for
isolated rain showers at RDD and RBL this afternoon and evening.
Otherwise, light (12 kts or less) southerly winds are expected.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$