Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/22/22
Area Forecast Discussion
National Weather Service Grand Rapids MI
945 PM EDT Fri Oct 21 2022
LATEST UPDATE...
Update
.UPDATE...
Issued at 940 PM EDT Fri Oct 21 2022
The main change to the forecast was to extend the small craft
advisory into Saturday. Low level wind fields remain strong over
Lake MI into Saturday. Incoming high res model data suggests 25
knots for all marine zones in our CWA are likely for at least part
of Saturday which could possibly top 30 knots north of Muskegon.
Based on this we were confident enough to stretch the headline
through Saturday afternoon. There are some indications that a lull
in the strong winds may occur for southern zones Saturday
evening...however it may not last long as the winds are shown to
pick up again for Sunday...although a southeasterly direction may
result.
&&
.DISCUSSION...(This evening through next Friday)
Issued at 340 PM EDT Fri Oct 21 2022
-- Sunny, Warm and Breezy Weekend --
Continued warm advection over the next few days ahead of an
evolving cyclone in the lee of the Rockies will send high
temperatures into the 70s. The air mass is very dry both overhead
and upstream with sfc dew pts in the 30s extending from MI as far
south as MO and TN. Much of the CONUS is cloud free and we should
continue to have mainly clear skies through Sunday. Expect breezy
southerly winds at times over the weekend, particularly during the
afternoon hours when deeper mixing is occurring.
-- Warmth Hangs on Early Next Week; Low Rain Chance --
Eventually a better influx of moisture off the Gulf takes place
early next week as a weakening cold front associated with nrn
Plains cyclone drifts farther east. This should result in an
increase in cloudiness as well as the possibility of a few
showers. Limiting factor will be the lingering dry air in the low
levels so this may be more of a virga/sprinkle type of deal on
Sunday night-Monday.
The better chance of rain probably holds off until mid week when
srn stream low moves northeast along stalled baroclinic zone.
However even this system could underperform QPF-wise since the nrn
stream doesn`t really phase in the with the energy passing
through the Ohio Valley Rgn. Either way it does look like we cool
off behind that system but temps will still continue to average
above normal behind it.
-- Longer Term Still Low Confidence --
Fcst confidence in the longer term still remains rather low as
cluster analysis during the mid to late week period continues to
offer differing scenarios on the H5 anomalies over the GrtLks Rgn.
It remains unclear where the mean longwave trough to our west
will be and we may end up being more under the influence of the
east coast ridging. Our temp fcst next Thur-Fri could need raised
in future updates if this is the case.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 730 PM EDT Fri Oct 21 2022
The surface winds will weaken this evening while the wind up
around 2k ft will remain strong. As a result an increased
potential for wind shear will exist at all sites tonight. The
gusty winds will resume Saturday morning and then persist for the
day. The atmosphere will be dry through a deep layer...thanks to
subsidence...so VFR weather is projected for the forecast period.
&&
.MARINE...
Issued at 340 PM EDT Fri Oct 21 2022
For now will keep the 2 AM expiration of the Small Craft Advisory
as is since guidance continues to show a lull occuring later
tonight into early Saturday. However if later updates of the HRRR
and NAMNest do not back off then extensions will be needed. Either
way the winds pick up again Saturday afternoon into Sunday but
with a slightly more offshore component (south-southeast wind
direction). Gut feel is that advisories will be needed for the Lk
MI nearshore most of the weekend.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...Small Craft Advisory until 6 PM EDT Saturday for LMZ844>849.
&&
$$
UPDATE...MJS
DISCUSSION...Meade
AVIATION...MJS
MARINE...Meade
Area Forecast Discussion
National Weather Service Medford OR
813 PM PDT Fri Oct 21 2022
>updated Marine Discussion.
.DISCUSSION...An update was sent to raise minimum temperatures
tonight, primarily due to the cloud cover and precipitation
expected over the region. The going forecast MinT grid appeared
to have too much bias-correction (which likely factored in the
clear, cool nights we`ve had for several mornings in a row). This
was especially the case for areas over the East Side. The clouds
should keep temperatures from dropping that low tonight -- the
exception being over the higher elevations, where colder air is
moving in (compared to recent nighttime temps). Preference was
given to the RAW guidance instead, which typically does better in
these cooler/wetter pattern change regimes.
Most of the remainder of the forecast looks to be in good shape.
It`s windy over the East Side, where some RAWS sites have gusted
in the 40-50 mph range. We have a wind advisory up til 2 am PDT.
A cold front is moving onshore currently and will move through
overnight, pushing SE of the area by Saturday morning. Recent 7 pm
web cams are showing rain! at the coast, in areas to the N&W of
Medford and over to the Cascades (as far south as Highway 140).
Expect this frontal rain to gradually move into the rest of the
Rogue Valley this evening and overnight, with just about everyone,
even areas east of the Cascades and in NorCal, getting at least a
little rain by sunrise Saturday. Post-frontal showers will
continue Saturday with the most activity focused along and west of
the Cascades/Siskiyous. There can also be thunderstorms across NW
sections as the cold pool aloft moves in. Please check out your
local point-and-click forecasts to see if thunder is forecast for
your specific location on weather.gov/mfr. Snow levels drop to
4000-5000 feet Saturday. Since it`s the first weather system
following a very warm period, snow accumulations will likely be
restricted to the highest elevations (mainly above 5000 feet). We
do have a Winter Weather Advisory up there til 5 am Sunday. So,
if you`re planning a trip up to Crater Lake this weekend, be
prepared for wintry conditions. Moist NW flow will continue
to produce showers into the Cascades through early Sunday
morning, but since the trough axis will be shifting to the east,
most of Sunday should turn out dry, albeit on the cool side.
-Spilde
&&
.AVIATION...22/00Z TAFs...Over the coastal waters, along the coast,
and in the coastal valleys...VFR conditions with local MVFR cigs
will prevail initially. An incoming front will bring areas of MVFR
cigs in low clouds and rain into Friday evening with higher terrain
becoming obscured. Showers and isolated thunderstorms will develop
Friday evening behind the front. These conditions will then persist
through Saturday.
From the Cascades westward...VFR conditions will persist into Friday
evening, except for areas of MVFR vsbys in haze and smoke in the
Umpqua Basin. An incoming front will bring areas of MVFR cigs in low
clouds and rain beginning Friday evening and spreading inland to
the Cascades Friday night with higher terrain becoming obscured.
Showers and isolated thunderstorms will develop Friday night
behind the front. These conditions will then persist through
Saturday.
East of the Cascades...VFR conditions will prevail through Friday.
Strong and gusty winds will continue through Friday night. An
incoming front will bring precipitation to the area beginning Friday
evening with areas of higher terrain becoming obscured. Showers will
develop Friday night behind the front. These conditions will then
persist through Saturday, except that winds will diminish
Saturday.
&&
.MARINE...Updated 800 PM PDT Friday 21 October 2022...A cold front
will move through the waters later this evening. South winds will
shift to the northwest and increase, with the strongest winds over
the northern outer waters with small craft conditions. A moderate
northwest swell will build tonight, bringing very steep seas to the
area. The swell will subside Sunday, and steep seas will persist
into Sunday evening. The pattern will remain active Monday into
Tuesday night with a couple more fronts moving through. High
pressure will build over the waters Wednesday. However, Another
round of moderate northwest swell will move through. -Petrucelli
&&
.PREV DISCUSSION... /Issued 306 PM PDT Fri Oct 21 2022/
SYNOPSIS...We are in a transition day before the first in a
series of fronts moves through southern Oregon and northern
California. This will provide several bursts of active weather for
the next several days with breaks in between.
Key Points:
* Gusty winds are expected today east of the Cascades. This may
cause issues for high profile vehicles, and could blow away
unsecured objects. Please see the NPWMFR for more details.
* Snow levels will begin at 9000 feet this evening and lower to
4000 feet on Saturday. Some accumulations are expected, largely
above 5000 feet. Snow will turn to snow showers
* We have issued a winter weather advisory for a portion of the
southern Oregon Cascades above 5000 feet. Please see the WSWMFR
for more details.
* There is a slight chance for a thunderstorm to occur on Saturday
along the coast, coast range, and Umpqua Valley.
DISCUSSION...Satellite imagery is showing some higher clouds
across most of southern Oregon and northern California. This is
indicative of the change in weather. Winds at Summer lake are
already beginning to gust near 40 mph, and expect this to continue
for most of the evening and overnight period. Have extended the
wind advisory until 5 AM for windy conditions. Please see the
NPWMFR for more details.
The HRRR model suggests that precipitation will begin at the coast
in a couple of hours (around 5 PM) and spreading inland over the
remainder of the evening. This seems reasonable. This rainfall
will likely be wetting for many areas of southern Oregon and
northern California. The heaviest precipitation amounts will be at
the Coos County Coast and Coast Range as well as for the Cascades
with lesser amounts in the valleys. In all, this rain will be
enough to likely bring fire season to a conclusion for a large
part of the area (but maybe not all of it quite yet). While this
might spark concerns for debris flows over burn scars, do not
believe that there will be high enough rain rates to create this.
This risk would increase a little on Saturday when rain rates
increase in showers, however the rainfall duration over the burn
scars in showers would likely be brief enough to keep the risk for
debris flows at extremely low levels.
Snow levels will start off around 9000 feet and drop to around
4000 on Saturday. After the front moves through showers of snow
will likely continue across the Cascades and portions of the East
Side. A winter weather advisory is in effect tonight from 5 AM
Saturday through 5 AM Sunday for a portion of the Cascades north
of Highway 140 above 5000 feet. While snowfall accumulations on
roads may be a little less than what is advertised in snowfall
amounts due to melting, some accumulations are possible on the
roads above 5000 feet. With it having been so warm as of late and
it being the first of the season, decided an advisory was
appropriate.
A break is expected on Sunday. With clearing skies, expect
temperatures to be pretty cold, likely coldest of the fall so far.
This may end summer growing seasons for many West Side Valleys
(maybe not for the Umpqua Basin). Freeze watches may be needed,
but will allow subsequent shifts to analyze those.
The next system appears to arrive next Tuesday night into
Wednesday. Ensembles are showing this to be another robust system
with additional periods of moderate rain with snow levels falling
back to around 4000 to 5000 feet. This system will have the chance
to produce additional impacts, so it is worth keeping an eye to
the forecast for more details. In fact, conditions are proving
favorable for increased active weather with the Climate Prediction
Center showing high confidence in above normal precipitation in
the 8 to 14 day outlook. This is good news for us for drought
concerns, but we would continue to rely on November, December, and
January to be active in order to really help with our ongoing
drought. -Schaaf
AVIATION...21/18Z TAFs...Over the coastal waters, along the coast,
and in the coastal valleys...VFR conditions with local MVFR cigs
will prevail initially. An incoming front will bring areas of MVFR
cigs in low clouds and rain Friday afternoon into Friday evening
with higher terrain becoming obscured. Showers and isolated
thunderstorms will develop Friday evening behind the front. These
conditions will then persist through Saturday.
From the Cascades westward...VFR conditions will persist into Friday
afternoon, except for areas of MVFR vsbys in haze and smoke in the
Umpqua Basin. An incoming front will bring areas of MVFR cigs in low
clouds and rain beginning Friday afternoon and spreading inland to
the Cascades Friday evening with higher terrain becoming obscured.
Showers and isolated thunderstorms will develop Friday evening
behind the front. These conditions will then persist through
Saturday.
East of the Cascades...VFR conditions will prevail through Friday.
Winds will become strong and gusty Friday afternoon and continue
through Friday night. An incoming front will bring precipitation to
the area beginning Friday evening with areas of higher terrain
becoming obscured. Showers will develop Friday night behind the
front. These conditions will then persist through Saturday, except
that winds will diminish Saturday.
MARINE...Updated 200 PM PDT Friday 21 October 2022...A cold front
will move onshore Friday evening. Moderate northwest swell will
build Friday night, bringing very steep seas to the area. The
swell will subside Sunday, and steep seas will persist into Sunday
evening. The pattern will remain active Monday into Tuesday with
more fronts moving onshore. High pressure will build over the
waters Wednesday. Another round of moderate northwest swell will
move through Wednesday.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory until 5 AM PDT Saturday for ORZ030-031.
Winter Weather Advisory from 5 AM Saturday to 5 AM PDT Sunday
for ORZ027-028.
CA...Wind Advisory until 5 AM PDT Saturday for CAZ085.
Pacific Coastal Waters...Hazardous Seas Warning from 11 PM this
evening to 5 AM PDT Sunday for PZZ350-356-370-376.
Small Craft Advisory from 5 AM to 11 PM PDT Sunday for PZZ350-
356-370-376.
Small Craft Advisory until 11 PM PDT this evening for PZZ370.
&&
$$
MAS/MAP
For frequently asked questions about the Area Forecast Discussion
visit...
http://weather.gov/saltlakecity/general/afd_faqs.php