Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/08/19

Area Forecast Discussion...UPDATED

National Weather Service Albuquerque NM

 502 PM MST Thu Nov 7 2019

.AVIATION...
00Z TAF CYCLE
Areas of fog and IFR/LIFR conditions are likely tonight, mainly for
central and ern NM. At this point, KABQ, KAEG and KSAF are the most
likely terminals to see at least brief, possibly dense, fog toward
sunrise Friday. Elsewhere, low stratus clouds will be the rule,
especially east of the central mt chain. The fog and low clouds are
forecast to gradually dissipate during the late morning and early
afternoon Friday. Winds will remain light for all TAF locales
through Friday.

33

&&

.PREV DISCUSSION...256 PM MST Thu Nov 7 2019...
.SYNOPSIS...
A gloomy day across central and eastern New Mexico today will turn
brighter Friday after cloud cover burns off in the morning. High
temperatures will trend warmer with readings closer to normal for
most of the area. Southeast New Mexico will remain cool where clouds
take the longest to burn off Friday. The remainder of the weekend
looks very nice with above normal temperatures, light winds, and
clear skies. A strong back door cold front will move into New Mexico
Sunday night and Veterans Day with much colder air through Tuesday.

&&

.DISCUSSION...
Cold and moist upslope flow over eastern NM has allowed widespread
low cigs with patchy fog to continue over the area today. A strong
1034 mb surface high over west Texas will slide east overnight as an
80-100 kt upper level jet moves eastward into the Great Plains. Low
level flow will slowly veer south then southwest by Friday morning
while much drier mid and upper level air slides overhead. This will
help erode low clouds and freezing fog along and east of the central
mt chain through noon. The HRRR fog product and RAP boundary layer
and surface wind profiles will remain favorable for dense freezing
fog to persist in the area from around Clines Corners to Ruidoso
overnight. A Freezing Fog Advisory has been issued for this area
with potential expansion into Guadalupe County and the Caprock.

Much drier air will invade the region from the northwest on Friday
as strong upper level high pressure builds into the Four Corners
region. This dry airmass with clear skies and light winds will lead
to a delightful weekend for most of the area with temps warming
above normal. The main exception will be over far southeastern NM
where low clouds may linger through Friday afternoon, followed by
more fog within the Pecos Valley of Chaves County Saturday morning.

The next back door cold front will slide into northeast NM Sunday
afternoon. This will be a stronger front than the most recent and
surge west into the RGV through Veterans Day. Temperatures will trend
below normal again for the entire area along with another round of
low clouds over eastern NM. An upper level low will be taking shape
over northern Mexico through this period however it looks too far
south to result in any mentionable precip chances for northern and
central NM at this time.

Guyer

&&

.FIRE WEATHER...
There are no critical fire weather conditions forecast for the next
7 days. However, widespread poor ventilation rates are forecast to
remain through Saturday. Temperatures today have been well below
normal for most, but will quickly rebound to above normal values by
the weekend. Dry conditions persist Friday and Saturday under
clearer skies, and vent rates will briefly trend up across southern
and eastern NM Sunday. However, temperatures and vent rates will
fall again behind a cold front that will move through the area
during the day Sunday. The cold front coinciding with a moisture
increase from the south could produce a few rain and snow showers in
the east on Monday, but precipitation is expected to remain light.

15

&&

.ABQ WATCHES/WARNINGS/ADVISORIES...
Freezing Fog Advisory until 4 AM MST Friday for the following
zones... NMZ223-226-239.

&&

$$

52



Area Forecast Discussion

National Weather Service Detroit/Pontiac MI

 941 PM EST Thu Nov 7 2019

.UPDATE...

Upper trough axis making steady progress across the lower peninsula
this evening - this motion prompting a slight veering of the 0-1 km
wind field with time. This process effectively eliminating the lake
Michigan moisture flux locally, as the resulting lower level drying
works into the increasing nocturnal stability to yield a steady
decline in both strato cu coverage and snowflake production across
the Saginaw valley and thumb region. There remains a transient
window roughly 10-14z tomorrow morning for a burst of moderate
intensity Lake Huron derived snowfall to glance across the eastern
thumb shoreline, as the existing lake aggregate trough and
corresponding convergence boundary pivot south-southeast. Recent
HRRR guidance more definitive now in keeping the bulk of this
response just offshore. This solution now in better agreement with
other model output, and absent of radar evidence to prove otherwise
yet, this leaves no compelling reason to deviate from the going
forecast of a couple of inches across a small geographic footprint
along the immediate shorelines of eastern Huron and Sanilac
counties.

&&

.PREV DISCUSSION...
Issued at 643 PM EST Thu Nov 7 2019

AVIATION...

A cold northwest flow will govern conditions through the overnight
period. This pattern will favor a gradually diminishing coverage of
strato cu within a drying low level environment this evening,
encouraged by the loss of daytime heating and a less favorable
downstream trajectory for the ongoing lake Michigan moisture flux to
manifest additional cloud. A prevailing modest northwest wind will
veer to westerly Friday as high pressure settles across the region.
Dry low level conditions favor plenty of open sky during the
daylight period, with simply a limited coverage of afternoon diurnal
strato cu.

DTW THRESHOLD PROBABILITIES...

* Low in ceilings at or below 5000 ft prior to midnight.

PREV DISCUSSION...
Issued at 339 PM EST Thu Nov 7 2019

DISCUSSION...

Upper level trough axis/cold pool (-24 C at 700 MB) sliding
through the Central Great Lakes this evening/tonight. Pronounced
low level anti-cyclonic flow over the bulk of southern Lower
Michigan today has kept snow shower activity out of southeast
Michigan thus far (through 2 PM), with decent amount of sunshine
allowing temps to rebound into the 30s.

However, it appears the Lake Superior-Lake Michigan-Saginaw Bay
connection will be in full effect this evening. 12z NAM sounding is
very impressive for BAD AXE, with good low to mid level lapse rates,
with capes up to 50 J/kg and very impressive cloud depths progged to
reach close to 12 kft, with a brief window of good supersaturation
with respect to ice. Confidence is high there will be numerous
convective snow showers around Saginaw Bay this evening, and have
ramped up pops north of M-46. A quick localized inch or two of snow
is possible over the northern thumb region with sufficient cape
intersecting the DGZ, but most places probably just picking up half
an inch or less due to short duration. Attention overnight/Friday
morning will turn to Lake Huron and whether the convergence band/lake
induced thermal trough will glance the eastern shoreline of the
Thumb Region. If the high building into northern Ontario overnight is
a bit stronger, than could see the HRRR/ARW solutions materialize,
which would be worthy of snow headlines with 850 MB temps of -12 to
-14 C over the Lake Huron water temps still 8 C. Some
concern/probability approaching 50 percent to issue Winter Storm
Watch for Huron County in the 9-16z window, just in case the band
makes better inroads into the eastern shoreline, supporting
localized heavy snow of 5+ inches. However, preference is to favor
the bulk of the solutions (NAM, etc) and keep enough of a northwest
component to keep the main Lake Huron band mainly offshore. Will
allow for a quick brush to the shoreline Friday AM (localized <3")
before the surface ridge moves in Friday afternoon.

Inherited mins tonight around 20 degrees looks good based on
guidance, with highs back into the 30s for tomorrow. Building
heights and low level warm advection will support a modest warmup
over the Weekend as wave of low pressure tracks through the northern
Great Lakes. Isentropic ascent/warm advection pattern perhaps
supporting a little bit of light snow and/or rain showers by
Saturday Evening/Night.

The extended forecast begins with ongoing rain showers Sunday
morning, but there could be frozen hydrometeors mixed in early on as
surface temps turn positive (degrees C) beneath narrowly saturated
low-levels. Ice nucleation will be relatively inefficient aloft as
the column becomes subsaturated wrt to ice in the DGZ, so actual
precip type may be more of a rain/ice pellet mix. Sunday will be the
warmest day of the total forecast period as highs creep into the 40s
CWA-wide. A cold front will cross through during the afternoon with
a good FGEN axis allowing for another bout of rain, but with the
colder air punch, a change over to all snow is expected by dark.
Winds back to the northwest and polar air surges through the Great
Lakes in the wake of the cold front as an upper level jet streak
pivots south locking in the polar air mass. Precip chances continue
on Monday as the right entrance region of a jet streak fuels
stronger upper level divergence generating broader ascent. 850 mb
temperatures now plunge to near -20 C which suggest sub-freezing
high temps on Monday. Given northerly low-level winds east of I-75,
there could be a period of lake effect snow showers which could
provide a good dose of snowfall, particularly in the Thumb as an
inverted surface trough helps increase low-level convergence.
Additional forcing will be provided by a shortwave trough deepening
within the broader longwave feature packing a good dose of higher
mid-level vorticity which will keep snow shower possibilities into
the early morning hours on Tuesday.

Surface ridge axis pushes into the Great Lakes from the Missouri
Valley on Tuesday as an expansive high builds east centering over
southern Illinois. Drier conditions will slowly take hold late
Tuesday and into early Wednesday as surface temps stay chilly. The
next trough moves through on Thursday, but moisture quality is still
a question mark before zonal flow backs to the southwest and another
inverted trough develops over Lake Huron.

MARINE...

Gusty west-northwest winds will prevail through the rest of the
evening before slowly weakening during the night and Friday morning
as high pressure nudges into the area from the west. Ongoing snow
squalls across Lake Huron will persist into the morning with the
cold air overhead. Southwest winds will strengthening Friday night
and into the day Saturday as a cold front slides into the northern
Great Lakes. Wind gusts are expected to remain below gale force.
However there is a high probability that gusts will reach 25 knots,
with up to 30 knots over the open waters of Lake Huron. Subtle
weakening of the wind field is forecast on Sunday before the actual
passage of the arctic cold front across the region late Sunday into
Sunday night. Winds will veer to the northwest with the passage of
this front.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...Lakeshore Flood Advisory until noon EST Friday for MIZ049.

Lake Huron...Small Craft Advisory until 10 AM EST Friday for LHZ421-441>443.

Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&

$$

UPDATE.......MR
AVIATION.....MR
DISCUSSION...SF/KK
MARINE.......SC


You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.




Area Forecast Discussion

National Weather Service Twin Cities/Chanhassen MN

 549 PM CST Thu Nov 7 2019

.SHORT TERM...(This evening through Friday night)
Issued at 210 PM CST Thu Nov 7 2019

Main concern in the short term is the overall temperature trend.

Stratocumulus over the eastern CWA should gradually dissipate this
evening as drier air works in from the west. Some mid clouds are
dropping fairly rapidly southeast and will likely clear the
southwest CWA by early evening. The surface ridge builds east
tonight and should provide mainly clear conditions along with
light wind. Temperatures should drop off to the single digits
again tonight over most of the snow covered areas. We even saw
some slightly below zero readings in south central MN last night.
This cold core should move east into Friday morning and southerly
winds are expected to increase with pressure falls and overall
pressure gradient increasing. Will be breezy west and south into
the afternoon and should help erode some of the cold air. Mainly
mid/high level clouds around much of the day should limit overall
sunshine potential. Highs Friday afternoon should rise to the
lower 40s in the far southwest with 30s generally elsewhere.

Decreasing winds Friday night with the area seeing warmer
temperatures. Lows should remain in the 20s overnight.

.LONG TERM...(Saturday through Thursday)
Issued at 210 PM CST Thu Nov 7 2019

The period will commence with MN/WI squarely within the warm
sector portion of a quick-moving clipper shifting east across the
international border on Saturday. While relatively deeper
moisture will be found in northern MN into the Great Lakes, a weak
surface trough dropping south from the main low will make for
enough lift to produce isolated to scattered rain/snow showers
over mainly central MN into western WI Saturday night into Sunday.
Not looking for anything significant by any means with this weak
and progressive system. Its associated cold front will drop
southeast through the region Saturday night, followed on its heels
by a 1048mb western Canadian high pressure airmass which will
slide into the Central Plains through early next week. A few snow
showers are possible in southwestern MN Sunday but by and large
the WFO MPX coverage area will remain dry late Sunday thru
Wednesday. That being said, this high pressure area will drag in
arctic air into the region which may well be cold enough to set
record low maximum temperatures early next week. H925-H850 temps
still look to drop to around -20 deg C which when blended to the
surface would produce highs in the teens Monday-Tuesday. In
addition, lows Sunday night and Monday night would drop to the
single digits. Combined with winds around 10mph, wind chills will
drop to the single digits below zero.

A small recovery is expected for the middle portion of next week
with the broad longwave trough moving east but this will also
bring in another clipper-type system from western Canada into the
Northern Plains Wednesday then into the Great Lakes Thursday.
Still plenty of uncertainty with this system as the operational
models have had different tracks of this system. Nevertheless,
profiles are showing plenty of cold air sufficient for snow
Wednesday into Thursday, just a matter of how much and where,
which should be resolved in the coming days.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 549 PM CST Thu Nov 7 2019

As high pressure slides east overnight, we will see light winds
quickly turn to a southerly direction. As this happens, band of
clouds over southwest MN will work northeast. Models have a poor
handle on this shallow cloud layer, but followed the idea of the
RAP for bringing this northeast across MN through the night. This
cloud layer will bring the potential for 2 or 3 hours of MVFR cigs
as it moves through a location. After that, just ample mid/upper
clouds for Friday.

KMSP...Currently, threat for MVFR cigs (likely around 025) at MSP
exists between 13z and 16z. Confidence in rest of TAF is high.

/OUTLOOK FOR KMSP/
Sat...MVFR. Chc IFR. Slgt chc rasn. Wind SW at 5-10 kts.
Sun...Chc MVFR cigs early. Wind NNW 10G20 kts.
Mon...VFR. Wind NW 10-15 kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
&&

$$

SHORT TERM...DWE
LONG TERM...JPC
AVIATION...MPG