Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/07/25
Area Forecast Discussion
National Weather Service Grand Rapids MI
953 PM EST Thu Mar 6 2025
.KEY MESSAGES...
- Small and low impact precipitation chances through Saturday night
- Dry and increasingly warmer Sunday through Tuesday
- Chance of rain next Wednesday
&&
.UPDATE...
Issued at 948 PM EST Thu Mar 6 2025
Skies are mostly clear across the cwa, but high clouds off to the
west will move across the cwa overnight. The current partly cloudy
forecast looks good. Winds have diminished under 10 mph at most
locations which will help temperatures fall into the lower to mid
20s overnight.
Regional radar shows weak echos over northern lower moving
southeast, which may clip the northeast cwa during the next few
hours; we`ll trim the PoPs farther west.
&&
.DISCUSSION...
Issued at 329 PM EST Thu Mar 6 2025
- Small and low impact precipitation chances through Saturday night
The last of the effects from the strong area of low pressure that
brought the rain, changing to snow, and gusty winds over the last
few days are in the process of ending for the area this afternoon.
Clouds are clearing out, and winds are gradually diminishing across
the area. The air is still a bit cool, but nothing bad by early
March standards.
After clearing this evening, we will see clouds spread back in over
most of the area overnight and Friday morning. There will be a small
chance of flurries/light snow showers later tonight north of I-96.
This very light precipitation will be the result of a weak short
wave that will clip the northern portion of the area. This short
wave will be significantly moisture starved with no real moisture
return in the lower levels ahead of it.
We continue to expect some light rain/snow for our southern portion
of the forecast area for much of Friday and Friday evening, mainly
south of I-96. This precipitation will be a bit more extensive then
the very light precipitation up north tonight. That is because this
system will have some phasing of weaker systems from the north and
south branches of the upper jet. In addition, the southern branch of
the jet will help to draw some moisture north from the Gulf.
Most of the energy with this system will stay south of the forecast
area. Southern Lower will be under the influence of mid level fgen
associated with the weak deformation zone of the phased mid level
wave. Enough moisture in the column will be present to allow
precipitation reach the ground. The precipitation will start off
initially as light snow, and could mix with/change over the rain in
the afternoon as sfc temps may warm just enough to see the change.
The increasing strength of the March sun on road temps should
mitigate any snowfall during the day. Can not rule out some light
accums early in the morning or at night as the precipitation is
winding down.
We will see one more small chance of a few light snow showers north
of I-96 Saturday night as one last short wave in the series clips
the northern portion of the state. This short wave will be moisture
starved again, so no accumulation is expected.
- Dry and increasingly warmer Sunday through Tuesday
Once the short wave Saturday night moves through, we will see rather
quiet weather with warming temperatures from Sunday through Tuesday.
The upper ridge that will be building to our west will slowly build
over our area then. This will push the main storm track well north
of our area, and provide dry weather with a lack of clouds for at
least Sunday into Tuesday.
While this is going on, low level return flow and the building
heights will push 850 mb temperatures up to almost +10C. If this
came to fruition, it is likely that we could be well into the 60s by
Tuesday ahead of a weak cold front that will try to move through the
area. This front looks to be dry without a good flow from the Gulf.
- Chance of rain next Wednesday
The front that drops through dry on Tuesday, looks to stall out just
to our south by Wednesday. At that time we will see additional
energy rotate in from the SW, and help to draw moisture back north
over the front.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 639 PM EST Thu Mar 6 2025
Expecting VFR much of tonight except in Central Michigan (north of
MKG, GRR, LAN) between 04Z and 09Z where MVFR ceilings are
possible with light snow showers. Then midday through evening
Friday, precipitation well to the north of a low-pressure system
over the Ohio valley is expected to develop over Southern
Michigan. This rain/snow mix is more likely than not to affect
AZO, BTL, and JXN, but whether it reaches GRR and LAN later in the
afternoon is still in question. This set of TAFs leans a little
on the pessimistic side for flight conditions, closer in the
direction of the 18Z HRRR which offers a more aggressive
solution. Overall, confidence remains fairly low in how far north
the worst conditions get. In general, expect more IFR Friday
afternoon in Southern Michigan (AZO, BTL, JXN), trending more VFR
to the north of MKG, GRR, and LAN.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 11 AM EST Friday for LMZ844>849.
&&
$$
UPDATE...04
DISCUSSION...NJJ
AVIATION...CAS
Area Forecast Discussion
National Weather Service Marquette MI
614 PM EST Thu Mar 6 2025
.KEY MESSAGES...
- Slight chance (~20%) for light snow progressing west to east
into this evening along a cold front, best chances this
evening over the east (20-40%).
- Seasonably chilly through Saturday, then temperatures warm
above normal for Sunday into early next week. No significant
precipitation is in the forecast at this time.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 321 PM EST Thu Mar 6 2025
Afternoon RAP analysis shows the strong CO low has made it well into
Quebec while weak high pressure and mid level ridging moves into the
Plains. WV imagery highlights a weak clipper low over NW Ontario,
extending a cold front across Lake Superior up against the W edge of
Upper MI. As this clipper continues SE this evening, eventually
phasing with the strong low over N Quebec, the weak cold front
progresses E across the CWA. Dry air from the W cleared skies out
this morning/early afternoon, and as a result, brought temps into
the upper 20s to mid 30s. This also has lowered dewpoints into the
teens to mid 20s. This ~10F dew point depression across the area
will be a limiting factor for any precip moving into this evening
with the passing cold front. So far cloud cover has increased over
the W and radar is showing light returns, however snow has not been
captured yet on webcams. This aligns well with the precip limiting
factor of dry low levels. Thus the forecast represents a brief
period of 15-20% chance for light snow progressing E across the UP
into this evening with up to 0.2" of snow possible in the highlands,
however most of the west will likely only see flurries at best.
Better chances for light snow are over the east (20-40%).
A cooler airmass filters in behind the cold front into Fri with
850mb temps back down to between -12C to -15C. This could support
some lake enhanced to eventually pure LES late over the NW wind snow
belts by Fri morning E of Munising (15-30% chance). Limited
available moisture tonight will keep accumulations likely around 1"
or less over the E. Otherwise some patchy blowing snow is possible
yet into tonight in the Keweenaw and by the Lake Superior shores
where gusty W to NW winds up to 25-35 mph are expected. Lows tonight
mainly fall into the teens, but the interior W could see some single
digits above 0F.
&&
.LONG TERM /FRIDAY THROUGH THURSDAY/...
Issued at 438 PM EST Thu Mar 6 2025
Cyclonic flow aloft on Fri alongside NW flow over Lake Superior
yielding lake sfc-850mb delta-Ts of 12-17C (higher over the NE
portion of the lake) supports some light LES over the NW wind snow
belts, mainly over the E. Unimpressive moisture and inversion
heights holding ~5kft or lower keep accumulations limited, with a
fluffy 1-3" possible by Saturday morning. Another possible mechanism
supporting light snow is a weak sfc trough and subtle shortwave
dropping SE over W Upper MI during the day Fri. QPF is light over
the W and placement is spread among the current suite of guidance.
Nonetheless, impacts are not anticipated with mainly 0.5" or less.
Otherwise, temps on Fri peak in the mid 20s to mid 30s with lows Fri
night in the single digits W and teens by the lakeshores and E as
weak high pressure moves overhead.
A shortwave approaching from the NW Fri night moves over N MN and WI
on Sat, bringing a weak clipper over the area into Sat night. With
the best lift and moisture remaining S of the CWA, only light
accumulations up to 0.5" are forecast along the WI/MI state line.
Trailing lake enhanced to marginally cold enough NW LES is possible
Sat night, mainly over the east.
Mid level ridging over the Rockies on Sunday progresses E across the
CONUS into next week as it flattens out, yielding a warming trend
Sat night into early next week. Highs Sun - Tue are likely to be in
the 40s save for Keweenaw County with a 33% chance for low 50s near
WI Mon/Tue. Some light snow showers over the far N can`t be ruled
out on Sun ahead of a clipper system tracking just N of Lake
Superior. Despite a stronger clipper system and deeper shortwave
tracking just north of Lake Superior Mon night into Tue, dry weather
looks to persist through mid next week.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 614 PM EST Thu Mar 6 2025
VFR conditions prevail through most of the TAF cycle. Main hazard at
CMX is gusty WNW winds to 30-35 kt, but those should quickly
diminish to 25 kt gusts or less for most of the night. Tomorrow,
look for borderline VFR/MVFR cigs to develop during the afternoon.
&&
.MARINE...
Issued at 438 PM EST Thu Mar 6 2025
West winds veer NW this evening behind a cold front with a few gale
force gusts to 35 kts possible tonight over the eastern third of the
lake (~30-50% chance). NW winds settle to 20 kts or less Friday
morning over the west half while 15-25 kt winds maintain over the
east half through the day. Winds veer north and settle below 20 kts
across the lake Friday night. Winds are expected to remain below 20
kts through Saturday night. A clipper system passing just north of
the lake Sunday afternoon into Monday increases southwest winds
during the day to 20-25 kts with winds veering northwest behind the
system into Monday. Northwest winds up to 30 kts are possible
Sunday night over the east half of the lake. Winds fall below 20
kts again for Monday, returning out of the south.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Jablonski
LONG TERM...Jablonski
AVIATION...Thompson
MARINE...Jablonski
Area Forecast Discussion
National Weather Service Phoenix AZ
549 PM MST Thu Mar 6 2025
.UPDATE...Updated Aviation Discussion.
&&
.SYNOPSIS...
Unsettled weather conditions will persist through the end of the
workweek as a couple weather disturbances traverse the region.
Breezy to locally windy conditions areawide today will be followed
by widespread precipitation chances and well below normal
temperatures tomorrow. Tranquil conditions and warming temperatures
can be expected as high pressure builds over the weekend. Another
series of weather systems will likely affect the region next week,
one late Monday into Tuesday and another during the latter half of
the week, turning conditions unsettled once again.
&&
.DISCUSSION...
Light shower activity associated with a cold front that passed
overhead this morning has moved well to the east of the Phoenix Area
and dissipated. Measurable rainfall amounts within the CWA have been
at or below 0.1" today, focused over NE La Paz, northern Maricopa,
and portions of southern Gila County. Behind the front, skies have
become mostly clear. The main concern through the remainder of the
day will be strong postfrontal winds out of the WSW, as guidance
continues to indicate 850 mb winds to 35-45 kts this afternoon, and
thanks to the sunny skies, daytime mixing should help some stronger
winds to be realized at the surface over the western deserts.
Widespread gusts to 25-35 mph will be common through the afternoon.
There will be a corridor of wind gusts exceeding 40 mph across much
of southeast CA through northern Yuma and La Paz Counties in
southwest AZ, and as such, Wind Advisories remain in effect through
early this evening for those areas. With the strong gusty winds,
there can also be areas of blowing dust resulting in temporary
reductions in visibilities. Lofted dust has already led to hazy
conditions for much of the area.
The core of a more potent upper low, evident in 500 mb RAP analysis
currently diving southward along the California Coast is expected to
pivot eastward over the region tomorrow. This will send another cold
front across the region, with a broad area of moist isentropic
ascent ahead of this feature bringing widespread precipitation to
the forecast area. Shower activity is expected to blossom over
portions of southeast CA and southwest AZ late tonight and then will
likely become more expansive as it moves into south-central AZ by
early Friday morning. Even though most of the activity will likely
be east of Phoenix by the late morning hours, some wrap around
showers associated with cold core will likely develop during the
afternoon hours, although activity will be more hit or miss. Total
QPF amounts from this system will range from less than 0.10" across
the western deserts, to between 0.25-0.5" across the south-central
AZ lower deserts, and between 0.6-1.0" across the foothills and
higher terrain areas to the north and east of Phoenix. As increased
cloud cover and a colder air mass will be over South-Central AZ
tomorrow, highs will struggle to reach 60F in the Phoenix Area,
though locations further west (e.g., Yuma, Blythe, El Centro) could
see highs in the upper 60s to near 70F Friday afternoon. Regardless,
these highs are around 8F-15F below normal for the time of year.
Given the cold core nature of this system, snow levels are likely to
drop pretty low close to 4000-4500 feet, yielding some snowfall
accumulations across the higher terrain areas. In fact, locations
above 5000 feet across southern Gila County through the Mazatzal,
Pinal and Superstition mountains will likely (HREF probabilities
near 80-95%) see accumulations locally exceeding 4" and thus Winter
Weather Advisories have been maintained for these locations from 6
AM to 5 PM MST Friday.
In the wake of the upper low, high pressure will build over much of
the Western US this weekend, leading to quieter weather and
warming temperatures into early next week. By Sunday, forecast
afternoon highs are near their normal values, in the middle to
upper 70s, and the NBM continues to advertise some of the
typically warmer lower desert locales potentially reaching the
lower 80s on Monday. Late Monday into Tuesday, ensembles are still
in fairly good agreement that another upper level trough will
influence the region, with some differences in timing apparent
between the WPC Clusters. However, all solutions look to result in
decent precipitation chances for the region, as the most likely
trajectory will be far enough south to bring better quality
moisture into the forecast area. Along with the increased
precipitation potential, there will be some locally gusty winds as
well as temperatures trending much cooler once again to below
normal levels. After this system departs eastward by midweek,
ensembles are in good agreement of yet another deep trough moving
through the western CONUS by the latter half of the week,
potentially bringing additional precipitation chances as well as
maintaining temperatures below normal.
&&
.AVIATION...Updated at 0048Z.
South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Low cigs, showers, and potential for reduced visibilities Friday
morning will be the main weather hazards this TAF period. Strong
winds gusting upwards of 25-30 kts will weaken through the evening
with directions favoring the W into the overnight period. Blowing
dust generated by this afternoon`s strong winds may result in
some slantwise visibility concerns through sunset. Confidence is
low in an easterly transition overnight with any easterly
transition expected to remain brief.
Confidence is excellent that widespread -SHRA will spread into the
Phoenix area just prior to sunrise Friday morning with cigs likely
falling into an MVFR category. There is a 20-30% chance of brief
IFR vsby/cig conditions in any heavier rainfall, but this category
would be rather brief into the mid morning hours. By late
morning, there may be more breaks in -SHRA activity, however
models suggest persistent MVFR cigs and more spotty -SHRA well
into the afternoon before clearing late afternoon prior to sunset
Friday afternoon. Thunderstorm chances Friday morning into the
afternoon will remain below 10%. VFR conditions will prevail by
late afternoon/early evening.
Southeast California/Southwest Arizona including KIPL and KBLH:
Very gusty SW winds with a few areas of lofted blowing dust will
remain the primary aviation weather concern through the next few
hours, then a period of -SHRA and cigs potentially touching in
MVFR category will be the primary weather impact late
tonight/early Friday morning. Gusts upwards of around 30 kts will
continue to weaken this evening, but any blowing dust generated
may result in some slantwise visibility issues through sunset.
Confidence is good that -SHRA and lowering cigs will arrive across
SE California around midnight, and impact the area during the
overnight hours. There`s a 20-40% chance of vsby/cigs touching
into MVFR category before conditions rapidly improve around
sunrise Friday morning. Gusty W/NW winds will increase late
morning into the afternoon with gusts climbing upwards of 20-25
kts.
&&
.FIRE WEATHER...
Unsettled weather conditions and well-below normal temperatures are
expected through Friday as a series weather disturbances move across
the region. Some shower activity is expected early this morning
along a cold front across portions of south-central AZ followed by
strong gusty winds later this morning and afternoon. Widespread
gusts ranging between 20-35 mph will be common with higher gusts in
excess of 40 mph across the western districts. More widespread
precipitation activity is expected on Friday with good chances
(>60%) of wetting rainfall across much of south- central AZ. MinRHs
through the end of the week will remain above 20%, with much of
south-central AZ likely remaining above 40% on Friday.
Warmer and drier conditions along with generally light winds can be
expected through the upcoming weekend. Conditions will then turn
unsettled once again next week as another series of weather systems
affect the region with one system moving through late Monday into
Tuesday and another by the latter half of the week. Both of these
systems will potentially result in more wetting rainfall, some gusty
winds, and temperatures cooling down once again to below normal
levels.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Wind Advisory until 7 PM MST this evening for AZZ530-531-533.
Winter Weather Advisory from 6 AM to 5 PM MST Friday for AZZ557-
558-563.
CA...Wind Advisory until 6 PM PST this evening for CAZ563>567-569-570.
Wind Advisory until 10 PM PST this evening for CAZ562.
&&
$$
DISCUSSION...Whittock/Lojero
AVIATION...Smith/18
FIRE WEATHER...Lojero